I have an HP Pavilion a1640n. Specs: http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&dlc=en&cc=us&docname=c00768103 The following items have been added from stock version. Windows 7 Professional Upgraded to 6GB of RAM Added 2T Seagate HDD A week ago my wife tripped the circuit breaker in the living room which shut off my HP, which I use for a media center PC. I restarted the computer and Windows would boot to a black screen with only the mouse pointer visible. Windows ended up doing start up recovery and disc error checking on reboot with a successful boot after error checking. The next day it would boot to black screen once again. I tried to running HD error checking with no success, then I tried to restore to a previous restore point but I was getting an error. I ended up just re-installing Windows. Occasionally ever since re-installing Windows I will hear loud beeps coming from what I believe is the HP computer (every 30 to 60 min). I've heard 4 short very loud beeps and 2 short very loud beeps while the computer is up and running. The beeps are so loud that I would almost compare them to a smoke detector. I've done HDD error checks with SpinRite (no unusual sounds coming form both HDD), I've even done error checks on the RAM with Ultimate boot CD and everything is running normal with no errors. Any suggestions would be greatly appreciated.