The computer POST (power-on self-test) checks a computer's internal hardware for compatibility and connection before starting the remainder of the boot process. If the computer passes the POST, the computer may give a single beep (some computers may beep twice) as it starts and continues to boot. However, if the computer fails the POST, the computer may generate a beep code telling the user the source of the problem.
The most common causes of POST failures are problems with the following components.
BIOS ROM
CPU (processor)
Motherboard
RAM (memory)
Video card
Except for Dell and Mac, your computer or motherboard manufacturer is not the BIOS manufacturer. Determine the BIOS manufacturer for your computer's motherboard, then select the appropriate link below for beep code meanings.
Dell beep codes
Beep Code Description
2 beeps Memory (RAM) not detected.
3 beeps Motherboard failure.
4 beeps Memory (RAM) failure.
5 beeps CMOS battery failure.
6 beeps Video card failure.
7 beeps Bad processor (CPU).
Lenovo beep codes
Beep Code Description
3 short beeps followed by 1 long beep. Memory not detected.
2 long beeps followed by 3 short beeps. Video card or on-board video not detected.
4 long beeps and Error 8998/8999 on the screen. Not enough shadow RAM resources or PCIe/PCI MMIO resources available.
2 short beeps. POST Error.
HP beep codes
Beep Code 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
2 short beeps, 2 long beeps BIOS recovery successful
Note: The following codes can vary depending on BIOS version.
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
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