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HP Desktop PCs - Computer Does Not Start and Emits an LED or Beep Code

This document pertains to HP and Compaq Desktop computers.

If your computer makes one or two short beeps before starting, this is normal and your computer is telling you that BIOS startup was successful. If your computer beeps and does not start, a more serious hardware issue is likely occurring. This support document contains information that can help you learn more about the issue and how to resolve the problem.

What to do when beep codes occur

An LED or beep code usually means a basic function was unable to start. A basic function might be reading memory, displaying video, or being able to send information to a hard drive. The most common problems that cause LED and beep codes are memory and heat-related failures caused by a build-up of dust in critical cooling areas.

Use the following steps when your computer emits an LED code or beep code:

Step 1: Removing dust from cooling areas on your computer

If your computer is new and has never been used before, you may skip this step.

Over time, dust can collect in the cooling vents of your computer. Too much dust can block airflow, causing sensitive components to overheat and fail. Before troubleshooting for startup codes, it is important to remove any dust that might have accumulated.

While wearing eye protection, use canned air or the end of a vacuum cleaner to remove dust from vents, preferably outdoors.

Figure 1: Vacuuming dust from air vents

End of vacuum cleaner nozzle over side panel vent

Step 2: Performing a power reset if your computer does not start

If your computer does not start, first reset all power to device. Hopefully, the problem is temporary and can be fixed by performing the following steps:

  1. Disconnect all peripheral devices such as printers, USB storage devices and media cards.

  2. Disconnect the power cord from the computer.

  3. Press and hold the power button for at least 15 seconds until the power LED on the power supply is off.

  4. Reconnect the power cord, and press the Power button.

  5. Listen for sounds of drives and fans turning.

  6. If the computer still fails to start and emits beeping sounds, continue to the next section.

Step 3: Writing down the LED condition or beep code for troubleshooting

Use the following steps to write down the error conditions onto a piece of paper.

  1. Press the power button to turn on the computer.

  2. Look at the Power button on your computer's case and note its condition. If the light blinks, count the number of times it blinks between pauses.

  3. Listen to your computer for any loud beeping noises. If your computer makes a beeping noise, note the type and number of beeps between pauses. For example: two long beeps followed by one short beep.

  4. On a piece of paper, write down what you have noted to remember the error when doing the next steps.

NOTE: Boot or post codes have changed over time. Earlier computers use a series of beeps. The number and type of beeps depend on the age of the computer as well as the manufacturer of the motherboard and BIOS. With the development of the Extensible Firmware Interface (EFI) environment, many HP Pavilion and Compaq Presario computers built in 2011 or later can use blinking LEDS to identify hardware component reporting an error during startup. These codes are not valid for earlier models.

Step 4: Matching the beep code to a suspected hardware component for troubleshooting

Consult the Beep code descriptions section in this support document to try and find the component that is having a problem. You can use this information in the next step when performing the troubleshooting. Or, in the event your computer requires service, you can use this code and information when talking with the service personnel.

Step 5: Isolating and fixing a beep code problem

HP recommends that only someone with experience in working on computer hardware perform these steps. Incorrectly handling sensitive internal components can further damage the computer and can introduce the risk of personal injury.

WARNING: Using the correct environment for working on computers (ESD precautions and tools), use the following steps to isolate and fix the problem:
  1. Turn on the computer.

  2. Check the system fan and power cable:

    1. Hold the power button for five seconds to turn off the computer.

    2. Disconnect the power cord and then disconnect all external cords from the computer.

    3. Remove the side panel to open the computer.

    4. If the system fan was not spinning, make sure the system fan power cable is connected to the correct pins on the motherboard. Replace the fan if it was making excessive noise or was not spinning.

      If you had to plug in or replace the fan, replace the side panel, plug in the power cord and turn on the computer. If the beeps continue, continue to the next step.

  3. Perform each of the following tasks, in order, until the beeping stops:

    Before starting each task, unplug the power cord, and then remove the side panel.

    After completing a task, replace the side panel, connect the power cord, turn on the computer, and then listen for a beep code.

    NOTE: If removing or disconnecting a hardware component prevents the beep code, that component is probably causing the problem. However, a failed motherboard might produce beep codes associated with a component other than the motherboard. If specific beep codes continue after replacing the corresponding component with a known good part, the system board might be failing to detect hardware changes and might require a replacement CPU, system board, or both.
    1. Clean internal cooling components that have become clogged with dust.

      If the beeping continues, continue to the next step.

    2. Remove each memory module, replacing the one that was previously removed.

      NOTE: For videos with product specific steps on how to remove and replace this part, please see the HP Service Media Library . Search for your computer for the specific steps for that computer.
      • If the computer stops beeping, the memory module might be bad, is the wrong type of memory for the motherboard, or was not fully seated or connected. Reinsert the memory module into the socket to see if a connection was the problem. If problems continue, replace the module.

      • If beeping continues after checking all the memory modules, continue to the next step.

    3. Remove the graphics adapter, if there is one.

      NOTE: For videos with product specific steps on how to remove and replace this part, please see the HP Service Media Library . Search for your computer for the specific steps for that computer.
      • If the beep code changes or continues with the same beep pattern after you remove the graphics adapter, the adapter might still be good. Reseat the graphics adapter into its socket and continue to the next step.

      • If the beep code goes away, the graphics adapter might be bad. Reseat the graphics adapter, making sure it is fully locked into the connector on the motherboard. If problems continue, replace the adapter.

    4. Remove each PCI card, replacing the one that was previously removed.

      NOTE: For videos with product specific steps on how to remove and replace this part, please see the HP Service Media Library . Search for your computer for the specific steps for that computer.
      • If the beep code goes away, the card might be bad. Reseat the card into its connector on the motherboard. If problems continue, replace the card.

      • If beeping continues after checking all cards, continue to the next step.

    5. Disconnect each hard drive and CD or DVD drive cable (IDE and ATA) from the motherboard socket, and then replace the one that was previously disconnected, until all cables have been checked.

      NOTE: For videos with product specific steps on how to remove and replace this part, please see the HP Service Media Library . Search for your computer for the specific steps for that computer.
      • If the beep code goes away, the cable or socket is probably bad. Look for bent pins inside the IDE socket on the motherboard and straighten any bent pins. Reseat the cables into the connectors. If problems continue, the drive itself might be bad and might need replacing.

      • If beeping continues after checking all connections, continue to the next step.

    6. At this point, the problem is probably the motherboard or processor. Make sure any jumpers on the motherboard have not fallen off their pins and into the case. Make sure the jumpers are set correctly. Otherwise, have a qualified service center or HP service the computer.

      NOTE: For videos with product specific steps on how to remove and replace this part, please see the HP Service Media Library . Search for your computer for the specific steps for that computer.

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Beep and LED code descriptions

Beep code tables are provided in the following sections of this document to help you isolate and understand the issue. This might reduce the time required to solve the problem. Read one of the following sections.

Flashing light codes

On some computers, the motherboard can flash or change the color of lights on the outside of the case, such as the power button LED and the hard drive activity LED. For computers that support this technology, lights blink and provide a beep to indicate a failure condition.

LED and beep condition
Description
Power button LED blinks 4 times with 4 beeps
Power Supply
Power button LED blinks 5 times with 5 beeps
Memory
Power button LED blinks 6 times with 6 beeps
Video Card or Graphics
Power button LED blinks 7 times with 7 beeps
Motherboard or System Board failure
Power button LED blinks 8 times with 8 beeps
BIOS or CMOS problem (ROM)

Example of LED conditions: click a menu item to view the condition

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Beep codes common to HP and Compaq Desktop computers

The following beep codes are common to many HP and Compaq desktop computers. Use these codes before referring to the other codes when they occur.

Beeps
Description
1 short beep and 1 long beep
Memory problem
2 short beeps and 1 long beep (repeats 5 times)
Unable to initialize video or video card required but not installed
3 short beeps and 1 long beep
CPU configuration error or CPU type is not compatible
The following beep codes are common to many HP and Compaq desktop computers that can occur while restoring, flashing or updating the BIOS:
Beeps
Description
1 short beep
Legacy floppy drive or CD/DVD drive not detected
2 short beeps
Floppy diskette or compact disc not detected
3 short beeps
Unable to start flashing (such as when missing a utility or BIOS image)
4 short beeps
Flashing failed (checksum error, corrupted image, etc.)
5 short beeps
BIOS recovery successful

Beep codes for American Megatrends, Inc (AMI) BIOS

The following AMI beep codes can occur when there is a problem during the attempt of a normal system startup. You can use these codes to help troubleshoot issues related to system startup. When troubleshooting further, please refer to the section What to do when beep codes occur .

NOTE: The following codes can vary depending on BIOS version.
Beeps
Description
1
Memory timing failure
2
Memory parity error
3
Memory read or write failure
4, 5, 6, 7
Fatal errors related to the operation of critical motherboard components - such as the CPU.
8
Video memory

The following table lists AMI beep codes that can occur when attempting to flash or recover the BIOS. You can use these codes to help troubleshoot problems related to system startup or flashing BIOS memory (such as in BIOS upgrades).

NOTE: The following codes can vary depending on BIOS version.
Number of beeps
Post code
1
No media detected
2
ROM file not found in root directory
3
Insert next media volume
4
Flash Programming successful
5
Failure while reading file
7
Flash EPROM not detected
10
Failure while erasing flash memory
11
Flash program error
12
Problem with ROM file size
13
ROM image does not match BIOS requirements

Beep codes for Award BIOS

Most Award post codes are displayed to screen. If a beep code occurs the problem is likely occurring before the system can display video (check the video card or memory).

NOTE: The following codes can vary depending on BIOS version.
Beeps
Description
1 short beep
POST process completed successfully - normal startup
1 long beep followed by 2 or 3 short beeps
Unable to initialize video (to display the post code)
Continuous beeping without pause
Serious system related issue such as CPU overheating
Other beep conditions
Memory errors.

Beep codes for Phoenix BIOS (for older computers)

You can use these codes to help troubleshoot issues related to system startup or flashing BIOS memory (such as in BIOS upgrades). When troubleshooting further, please refer to the section What to do when beep codes occur .

Four series of beeps indicate a fatal error; that is, a problem exists which prevents the computer from starting. For example, there might be two beeps, a short pause, one beep, a short pause, one beep, a short pause, and then three beeps; this is represented as 2-1-1-3 in the chart below.

NOTE: The following codes can vary depending on BIOS version.
Beeps
Post Code
Description of failure
One short beep
0
POST process completed successfully - normal startup
1-1-1-3
02h
Verify real mode
1-1-2-1
04h
Get CPU type
1-1-2-3
06h
Initialize system hardware
1-1-3-1
08h
Initialize chipset registers with initial POST values
1-1-3-2
09h
Set in POST flag
1-1-3-3
0Ah
Initialize CPU registers
1-1-4-1
0Ch
Initialize cache to initial POST values
1-1-4-3
0Eh
Initialize I/O
1-2-1-1
10h
Initialize Power Management
1-2-1-2
11h
Load alternate registers with initial POST values
1-2-1-3
12h
Jump to UserPatch0
1-2-2-1
14h
Initialize keyboard controller
1-2-2-3
16h
BIOS ROM checksum
1-2-3-1
18h
8254 timer initialization
1-2-3-3
1Ah
8237 DMA controller initialization
1-2-4-1
1Ch
Reset Programmable Interrupt Controller
1-3-1-1
20h
Test DRAM refresh
1-3-1-3
22h
Test 8742 Keyboard Controller
1-3-2-1
24h
Set ES segment register to 4 GB
1-3-3-1
28h
Autosize DRAM
1-3-3-3
2Ah
Clear 512K base RAM
1-3-4-1
2Ch
Test 512 base address lines
1-3-4-3
2Eh
Test 512K base memory
1-4-1-3
32h
Test CPU bus-clock frequency
1-4-2-1
34h
CMOS RAM read/write failure
1-4-2-4
37h
Reinitialize the chipset
1-4-3-1
38h
Shadow system BIOS ROM
1-4-3-2
39h
Reinitialize the cache
1-4-3-3
3Ah
Autosize cache
1-4-4-1
3Ch
Configure advanced chipset registers
1-4-4-2
3Dh
Load alternate registers with CMOS values
2-1-1-1
40h
Set Initial CPU speed
2-1-1-3
42hs
Initialize interrupt vector
2-1-2-1
44h
Initialize BIOS interrupts
2-1-2-3
46h
Check ROM copyright notice
2-1-2-4
47h
Initialize manager for PCI Options ROMs
2-1-3-1
48h
Check video configuration against CMOS
2-1-3-2
49h
Initialize PCI bus and devices
2-1-3-3
4Ah
Initialize all video adapters in system
2-1-4-1
4Ch
Shadow video BIOS ROM
2-1-4-3
4Eh
Display copyright notice
2-2-1-1
50h
Display CPU type and speed
2-2-1-3
52h
Test keyboard
2-2-2-1
54h
Set key click if enabled
2-2-2-3
56h
Enable keyboard
2-2-3-1
58h
Test for unexpected interrupts
2-2-3-3
5Ah
Display prompt "Press F2 to enter SETUP"
2-2-4-1
5Ch
Test RAM between 512 and 640k
2-3-1-1
60h
Test expanded memory
2-3-1-3
62h
Test extended memory address lines
2-3-2-1
64h
Jump to UserPatch1
2-3-2-3
66h
Configure advanced cache registers
2-3-3-1
68h
Enable external and CPU caches
2-3-3-2
69h
Initialize SMI handler
2-3-3-3
6Ah
Display external cache size
2-3-4-1
6Ch
Display shadow message
2-3-4-3
6Eh
Display non-disposable segments
2-4-1-1
70h
Display error messages
2-4-1-3
72h
Check for configuration errors
2-4-2-1
74h
Test real-time clock
2-4-2-3
76h
Check for keyboard errors
2-4-4-1
7Ch
Set up hardware interrupts vectors
2-4-4-3
7Eh
Test coprocessor if present
3-1-1-1
80h
Disable onboard I/O ports
3-1-1-3
82h
Detect and install external RS232 ports
3-1-2-1
84h
Detect and install external parallel ports
3-1-2-3
86h
Re-initialize onboard I/O ports
3-1-3-1
88h
Initialize BIOS data area
3-1-3-3
8Ah
Initialize extended BIOS data area
3-1-4-1
8Ch
Initialize floppy controller
3-2-1-1
90h
Initialize hard-disk controller
3-2-1-2
91h
Initialize local-bus hard-disk controller
3-2-1-3
92h
Jump to UserPatch2
3-2-2-1
94h
Disable A20 address line
3-2-2-3
96h
Clear huge ES segment register
3-2-3-1
98h
Search for option ROMs
3-2-3-3
9Ah
Shadow option ROMs
3-2-4-1
9Ch
Set up Power Management
3-2-4-3
9Eh
Enable hardware interrupts
3-3-1-1
A0h
Set time of day
3-3-1-3
A2h
Check key lock
3-3-3-1
A8h
Erase F2 prompt
3-3-3-3
Aah
Scan for F2 key stroke
3-3-4-1
AChP
Enter SETUP
3-3-4-3
Aeh
Clear in-POST flag
3-4-1-1
B0h
Check for errors
3-4-1-3
B2h
POST done--prepare to boot operating system
3-4-2-1
B4h
One beep
3-4-2-3
B6h
Check password (optional)
3-4-3-1
B8h
Clear global descriptor table
3-4-4-1
BCh
Clear parity checkers
3-4-4-3
Beh
Clear screen (optional)
3-4-4-4
BFh
Check virus and backup reminders
4-1-1-1
C0h
Try to boot with INT 19
4-2-1-1
D0h
Interrupt handler error
4-2-1-3
D2h
Unknown interrupt error
4-2-2-1
D4h
Pending interrupt error
4-2-2-3
D6h
Initialize option ROM error
4-2-3-1
D8h
Shutdown error
4-2-3-3
Dah
Extended Block Move
4-2-4-1
DCh
Shutdown error
4-2-4-3
Deh
Keyboard Controller Failure
4-3-1-3
E2h
Initialize the chipset
4-3-1-4
E3h
Initialize refresh counter
4-3-2-1
E4h
Check for Forced Flash
4-3-2-2
E5h
Check HW status of ROM
4-3-2-3
E6h
BIOS ROM is OK
4-3-2-4
E7h
Do a complete RAM test
4-3-3-1
E8h
Do OEM initialization
4-3-3-2
E9h
Initialize interrupt controller
4-3-3-3
Eah
Read in bootstrap code
4-3-3-4
Ebh
Initialize all vectors
4-3-4-1
Ech
Boot the Flash program
4-3-4-2
Edh
Initialize the boot device
4-3-4-3
Eeh
Boot code was read OK

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Testing computer memory for troubleshooting

If the computer can access part of the memory, it might be possible to access the BIOS Setup Utility display and perform a memory self-test to identify other memory issues. If the computer cannot boot to the BIOS Utility, try removing and reseating the memory and the hard drive, and then repeat the following steps to perform the memory self-test.

  1. Plug the AC adapter into the computer.

  2. Turn off the computer.

  3. Press the Power button to start the computer and repeatedly press the f10 key to enter the BIOS Setup menu.

  4. In the BIOS Setup Utility, use the Right Arrow or Left Arrow keys to navigate through the menu selection to locate the Diagnostics.

  5. Use the Down Arrow or Up Arrow keys to select Memory Test.

  6. Press Enter, and then Yes to perform memory test.

  7. After test completes, press f10 key to Save and Exit, and then press Enter key to Exit Saving Changes.

If the test fails, one or more of the memory modules might not be seated properly. Check for and reseat loose memory modules.

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Finding repair service

Many of the problems associated with LED or beep codes require service or parts replacement. To find an HP authorized service provide, go to www.hp.com/go/support .

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