Hi, this has been happening for a while my computer was made from parts bought from frys and i made sure that all parts i am using is compattable with my motherboard my mother board is a P5N-E sli a Sata hard drive an Nvidia 8800gts 512mb---- 500wats powersupply Intel core 2 duo 2.33 ghz ( never been over clocked ) my computer runs for about 20mins- 1hr without doing this beep THIS BEEP IS ONE LONG BEEP IT NEVER CHANGES IT IS THE SAME TONE AND NEVER STOPS. IT IS ONE CONTINUES BEEP NOT A SERIES PLEASE HELP ME