BIOS Beep Codes
An introduction to BIOS beep codes
When you power on your computer, the motherboard's basic input/output system (BIOS) first detects the computer's internal hardware configuration and then performs the power-on self-test (POST). The POST executes several diagnostic tests that check the basic functionality of the power supply, motherboard, CPU, I/O Bus Controller, RAM, keyboard, and video components. If the computer passes the POST, it will usually return a single short beep or two short beeps, depending on the BIOS manufacturer. If the POST detects any problems, it will halt the boot process and return an error message either visually on the screen and/or audibly through a series of beeps.
Unfortunately, there is no official standard for beep codes. Depending on the BIOS manufacturer, a keyboard controller failure could be three, four, five, or six beeps. While this document lists common BIOS manufacturer beep codes, you should always consult your motherboard's documentation, the manufacturer's Web site, and the BIOS manufacturer's Web site for a definitive beep code list for your particular BIOS. The information contained in the following lists was gathered from various BIOS manufacturers' Web sites.