When a computer is booted up its BIOS, it performs a power-on self test, also known as POST, to test and verify the computers hardware and to make sure all components are working properly. Here's a comprehensive guide on how to determine which component has failed on a particular beep code and give you an idea on where to start for troubleshooting.
The exact meaning of the beep codes depends on the type and version of BIOS that you have. The three most popular types of BIOS are those made by Award, American Megatrends (AMI) and Phoenix. If you are using a PC made by a company that writes its own BIOS, e.g. DELL, HP, etc, you will have to consult your PC user's manual or the company's web site for assistance.
Beep Codes for Award Bios
1 long, 2 short
= Video adapter error
Troubleshooting: Either video adapter is bad or is not seated properly. Repeating (endless loop)
= Memory error
Troubleshooting: Check for improperly seated or missing memory. Reseat the memory if you can.1 long, 3 short
= No video card or bad video RAM.
Troubleshooting: Reseat or replace the video card.High frequency beeps while running
= Overheated CPU
Troubleshooting: Check the CPU fan for proper operation. Check the case for proper air flow.Repeating High/Low
= CPU failure.Either the CPU is not seated properly or the CPU is damaged. May also be due to excess heat.
Troubleshooting: Check the CPU fan or BIOS settings for proper fan speed.
I will be posting more tips on other versions of BIOS.
Hope this helps.