Sounds like you need to replace your motherboard. Unfortunately you'll have to get a compaq replacement for that system, as standard MB's usually won't work in compaq PC's (the front panel/power switch connection is usually proprietary). I did a quick search and I found your model on HP's parts website ( http://h20141.www2.hp.com/hpparts/Search_Results.asp?mscssid=W7P4LJUFW45X8HGEENKKJXK82JPQ3GUC) , but it looks like they don't stock it any more. A quick Google for the part # came up with a price of $189. Pretty steep once you add shipping and taxes. Depending on the status of your other PC, you may just want to slave your Compaq PC drive into it and access your data that way.