If your computer beeps and fails to boot

On startup, computers perform a Power-on Self Test, commonly referred to as a POST. If problems are found while booting, you can usually diagnose them using the error codes displayed on the screen. However, if nothing displays on the screen, the computer might use sounds (i.e., beep codes) to tell you what is wrong. Many of these errors indicate hardware problems that a service technician should fix. However, some errors are easily fixed. For example, keyboard controller errors often mean that your keyboard isn't plugged in.

Following are beep codes for some common brands of BIOS for PCs. For information about Mac beep codes or startup tones, see Apple Support's About Mac computer startup tones.

Many BIOSes will have different beep codes even if they appear to be from the same manufacturer. This is because motherboard manufacturers reprogram codes to reflect their own customizations. You can often go to the website for the motherboard's manufacturer to find the updated codes, but you may find cases where the manufacturer simply does not document the changes.

For more about beeps and error codes, see ComputerHope.com's Computer POST and beep codes.

On this page:


Award BIOSes typically use more screen errors than beep codes.

For Award BIOSes manufactured by Phoenix Technologies, note the following from the Phoenix Technologies AwardBIOS Error Messages page:

"The only AwardBIOS beep code indicates that a video error has occurred and the BIOS cannot initialize the video screen to display any additional information. This beep code consists of a single long beep followed by two short beeps. Any other beeps are probably RAM (Random Access Memory) problems."

Award BIOSes not manufactured under Phoenix Technologies use the following beeps; this information is from the BIOS Central Award BIOS Beep Codes page:

Beeps Meaning
1 long, 2 short
Video adapter error: Bad or improperly seated video card
Repeating beeps
Memory error: Bad or improperly seated RAM
1 long, 3 short
Bad video RAM or video card not present
High-frequency beeps Overheated CPU: Check fans
Repeating high/low beeps
CPU: Improperly seated or defective CPU

AMI (American Megatrends)

The information below is from the BIOS Central AMI BIOS Beep Codes page.

Beeps Meaning
1 short DRAM refresh failure
2 short
Parity circuit failure in the first 64 KB of RAM: Likely a bad RAM IC, or possibly one of the hardware tests has failed
3 short
Memory failure in the first 64 KB of RAM: Likely a bad RAM IC
4 short
System timer failure: Bad clock IC or bad RAM in the first bank of memory
5 short
Processor failure: The CPU has failed.
6 short
Keyboard controller Gate A20 error: The keyboard controller has failed. Due to its integration into the system board, you usually must replace the motherboard.
7 short
Virtual mode exception error: CPU has generated an exception error; bad CPU or motherboard
8 short
Display memory Read/Write test failure: Bad video card
9 short
ROM BIOS checksum failure: BIOS is defective
10 short
CMOS shutdown Read/Write error
11 short
Cache Memory error: Specifically, the L2 cache is bad.
1 long, 2 short
Video system failure: Error in video card BIOS, or a horizontal retrace has failed
1 long, 3 short
Conventional/Extended memory failure: RAM is bad
1 long, 8 short
Display/Retrace test failed: Video adapter is defective or missing


The following information is from the BIOS Central AST BIOS Beep Codes page.

Beeps Meaning
1 short
CPU register test failure: The CPU has failed.
2 short
Keyboard controller buffer failure: The keyboard controller has failed.
3 short
Keyboard controller reset failure: The keyboard controller has failed or the motherboard circuitry is faulty.
4 short
Keyboard communication failure: Bad keyboard controller or keyboard
5 short
Keyboard input failure: The keyboard controller IC has failed.
6 short
System board chipset failure: The chipset on the motherboard has failed. Replace the motherboard.
9 short
BIOS ROM checksum error: The BIOS ROM has failed. If possible, replace the BIOS on the motherboard.
10 short
System timer test failure: The system clock IC has failed.
11 short
ASIC failure: Motherboard circuitry has failed. Replace the motherboard.
12 short
CMOS RAM shutdown register failure: The real-time clock/CMOS IC failed. Replace the CMOS or motherboard.
1 long
DMA controller 0 failure: The DMA controller IC for channel 0 has failed. If possible, replace the IC.
1 long, 1 short
DMA controller 1 failure: The DMA controller IC for channel 1 has failed. If possible, replace the IC.
1 long, 2 short
Video vertical retrace failure: The video adapter has probably failed. Replace the video adapter.
1 long, 3 short
Video memory test failure: The video adapter's memory has failed. Replace the video adapter.
1 long, 4 short
Video adapter failure: The video adapter has failed. Replace the video adapter.
1 long, 5 short
64 KB memory failure: A failure has occurred in the base 64 KB of memory. If possible, replace the RAM IC.
1 long, 6 short
Unable to load interrupt vectors: The BIOS was unable to load the interrupt vectors into memory.
1 long, 7 short
Unable to initialize video: This is a video problem. Replace the video adapter first. If the problem persists, replace the motherboard.
1 long, 8 short
Video memory failure: There is a failure in the video memory. Replace the video adapter first. If the problem persists, replace the motherboard.


The following information is from the BIOS Central Compaq BIOS Beep Codes page.

Beeps Meaning
1 short
No error: The system is booting properly.
1 long, 1 short
BIOS ROM checksum error: The contents of the BIOS ROM do not match the expected contents. If possible, reload the BIOS from the PAQ.
2 short
General error: No specifics available on what this code means
1 long, 2 short
Video error: Check the video adapter and make sure it's seated properly. If possible, replace the video adapter.
7 beeps (1 long, 1 short, 1 long, 1 short, pause, 1 long, 1 short, 1 short)
AGP video: The AGP video card is faulty. Reseat the card or replace it outright. This beep pertains to Compaq Deskpro systems.
Continuous beep
Memory error: Bad RAM; replace and test
1 short, 2 long
Bad RAM: Reseat RAM, then retest; replace RAM if failure continues.


The following information applies to Phoenix BIOS Q3.07 or 4.x. This information is from the Phoenix BIOS beep codes section of the ComputerHope.com Computer POST and beep codes page.

Dashes indicate pauses between beeps.

Beeps Meaning
1-1-1-3 Verify real mode.
1-1-2-1 Get CPU type.
1-1-2-3 Initialize system hardware.
Initialize chipset registers with initial POST values.
1-1-3-2 Set in POST flag.
1-1-3-3 Initialize CPU registers.
Initialize cache to initial POST values.
1-1-4-3 Initialize I/O.
1-2-1-1 Initialize Power Management.
Load alternate registers with initial POST values.
1-2-1-3 Jump to UserPatch0.
Initialize keyboard controller.
1-2-2-3 BIOS ROM checksum
1-2-3-1 8254 timer initialization
8237 DMA controller initialization
Reset Programmable Interrupt Controller.
1-3-1-1 Test DRAM refresh.
Test 8742 Keyboard Controller.
Set ES segment to register to 4 GB.
1-3-3-1 28 Autosize DRAM.
1-3-3-3 Clear 512 KB base RAM.
Test 512 KB base address lines.
1-3-4-3 Test 512 KB base memory.
1-4-1-3 Test CPU bus-clock frequency.
1-4-2-4 Reinitialize the chipset.
1-4-3-1 Shadow system BIOS ROM.
1-4-3-2 Reinitialize the cache.
1-4-3-3 Autosize cache.
Configure advanced chipset registers.
Load alternate registers with CMOS values.
2-1-1-1 Set Initial CPU speed.
2-1-1-3 Initialize interrupt vectors.
2-1-2-1 Initialize BIOS interrupts.
2-1-2-3 Check ROM copyright notice.
Initialize manager for PCI Options ROMs.
Check video configuration against CMOS.
Initialize PCI bus and devices.
Initialize all video adapters in system.
2-1-4-1 Shadow video BIOS ROM.
2-1-4-3 Display copyright notice.
2-2-1-1 Display CPU type and speed.
2-2-1-3 Test keyboard.
2-2-2-1 Set key click if enabled.
2-2-2-3 56 Enable keyboard.
Test for unexpected interrupts.
Display message "Press F2 to enter SETUP".
Test RAM between 512 and 640 KB.
2-3-1-1 Test expanded memory.
Test extended memory address lines.
2-3-2-1 Jump to UserPatch1.
Configure advanced cache registers.
Enable external and CPU caches.
2-3-3-3 Display external cache size.
2-3-4-1 Display shadow message.
Display non-disposable segments.
2-4-1-1 Display error messages.
Check for configuration errors.
2-4-2-1 Test real-time clock.
2-4-2-3 Check for keyboard errors.
Set up hardware interrupts vectors.
2-4-4-3 Test coprocessor if present.
3-1-1-1 Disable onboard I/O ports.
Detect and install external RS232 ports.
Detect and install external parallel ports.
Re-initialize onboard I/O ports.
3-1-3-1 Initialize BIOS Data Area.
Initialize Extended BIOS Data Area.
3-1-4-1 Initialize floppy controller.
Initialize hard-disk controller.
Initialize local-bus hard-disk controller.
3-2-1-3 Jump to UserPatch2.
3-2-2-1 Disable A20 address line.
Clear huge ES segment register.
3-2-3-1 Search for option ROMs.
3-2-3-3 Shadow option ROMs.
3-2-4-1 Set up Power Management.
3-2-4-3 Enable hardware interrupts.
3-3-1-1 Set time of day.
3-3-1-3 Check key lock.
3-3-3-1 Erase "F2" message.
3-3-3-3 Scan for F2 keystroke.
3-3-4-1 Enter SETUP.
3-3-4-3 Clear in-POST flag.
3-4-1-1 Check for errors.
POST complete; prepare to boot operating system.
3-4-2-1 One beep.
3-4-2-3 Check password (optional).
Clear global descriptor table.
3-4-4-1 Clear parity checkers.
3-4-4-3 Clear screen (optional).
Check virus and backup reminders.
4-1-1-1 Try to boot with INT 19.
4-2-1-1 Interrupt handler error.
4-2-1-3 Unknown interrupt error.
4-2-2-1 Pending interrupt error.
4-2-2-3 Initialize option ROM error.
4-2-3-1 Shutdown error.
4-2-3-3 Extended Block Move.
4-2-4-1 Shutdown 10 error.
4-3-1-3 Initialize the chipset.
4-3-1-4 Initialize refresh counter.
4-3-2-1 Check for Forced Flash.
4-3-2-2 Check HW status of ROM.
4-3-2-3 BIOS ROM is okay.
4-3-2-4 Do a complete RAM test.
4-3-3-1 Do OEM initialization.
Initialize interrupt controller.
4-3-3-3 Read in bootstrap code.
4-3-3-4 Initialize all vectors.
4-3-4-1 Boot the Flash program.
4-3-4-2 Initialize the boot device.
4-3-4-3 Boot code was read okay.

IBM Desktop

Beeps Meaning
No beep
No power, loose expansion card (ISA, PCI, or AGP), a short, or an improperly grounded motherboard
1 short System okay
1 long
Video/display problem; video card incorrectly seated or defective
2 short
POST Error displayed on monitor
3 long
Problem with 3270 keyboard card
1 long, 1 short Problem with system board
1 long, 2 short
Problem with display adapter (MDA, CGA)
1 long, 3 short Problem with EGA
Repeating short beeps
Problem with power supply or system board
Continuous beep
Problem with power supply or system board

IBM ThinkPad

Beeps Meaning
Continuous beeping System board failure
1 beep with blank display
LCD connector problem, LCD backlight inverter failure, video adapter failure, or LCD assembly failure
1 beep w/message "Unable to access boot source"
Boot device failure or bad system board
1 long, 2 short
System board, video adapter, or LCD assembly failure
1 long, 4 short Low battery voltage
1 beep every second Low battery voltage
2 short w/message
Read the error message on the display
2 short with blank display System board failure


Beeps Meaning
1 Normal boot: No problems
Video adapter error: Video adapter is not seated or is faulty
Keyboard controller error: Keyboard controller IC bad
Keyboard error: Keyboard itself might be bad, or the controller IC on the motherboard
PIC 0 error: The programmable interrupt controller IC is bad
6 PIC 1 error: Same as above
DMA page register error: DMA controller IC is bad
8 RAM refresh error
9 RAM data error
10 RAM parity error
DMA controller 0 error: DMA controller IC for channel 0 has failed
12 CMOS RAM error: Bad CMOS RAM
DMA controller 1 error: DMA controller IC for channel 1 has failed
CMOS RAM battery error: Dead CMOS battery; can usually be replaced
CMOS RAM checksum error: CMOS RAM failed
BIOS ROM checksum error: BIOS RAM failed

Quadtel BIOS

The following information is from the BIOS Central Quadtel BIOS Beep Codes page.

1 short
Normal boot: System is booting normally.
2 short
CMOS IC error: The CMOS RAM is faulty. Replace the IC if possible.
1 long, 2 short
Video failure: The video adapter is faulty. Reseat the video adapter or replace the adapter if possible.
1 long, 3 short
Peripheral controller error: One or more of the system peripheral controllers is bad. Replace the controllers and retest.

This is document afzy in the Knowledge Base.
Last modified on 2017-12-20 14:44:36.

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