ok when i appemt to restart my dads computer all i get is a black screen and a beep which is not like most beep codes ive heard but is more like a siren. EEOOEEOOEEOOEEOOEEOOEEOO.... like a firetruck or something! its a P4 2.0,512 mb ram, 30 gb HDD, AOpen board, Win XP, geforce4 video card. i think its an Award BIOS. Thanks.

From the PC Guide:

Award Bios Beep Codes:

"Continuous Beeping: Memory or video problem

Explanation: The system is producing constant beeping in no specific pattern, or a fast "ringing" sound.

Diagnosis: This is usually caused by a problem with the system memory, or possibly the video card. The memory is more likely--the system complains long and loud if it can't find any usable memory, as there is no way to even start the boot process when this is the case. The motherboard itself could also be the problem."

If you have two memory sticks, try one first, then the other.