What you are hearing are beep codes, the PC's attempt to talk to you about a problem it is having. I find that almost all motherboards adhere to the IBM BIOS standard beep codes, although a few OEM's have developed their own or use Phoenix or AMI beep codes. In general, motherboard manufacturers use the IBM codes because they are "standard."

 

The beeps you describe (continuous hi-lo alternated beeping in the IBM scheme) indicate that the CPU is overheating.

 

1. Turn off the PC. Check to make sure that all fans are clean, clear of dust and debris, and turn freely.

2. Check to see that (when the PC is on), the fan(s) run - no motors burned out.

3. Check to make sure the CPU is seated properly (has not experienced "chip creep").

4. If none of the above resolve this, adding a muffin fan to the chip if there is none may end the problem.

 

If nothing has helped at this point, it may be time to admit defeat and replace the old PC.

 

For further information on PC beep codes, refer to http://www.computerhope.com/beep.htm