Originally Posted by linnerd40
Use system restore, and select the eariliest date you can.
as much as we would like to beleive thats as good as reformatting, it usually isn't. if you have a limit on the size of system restore files your computer may store, (which most computers do unless you change the setting), then your earliest system restore date may very well be nowhere near the factory settings.
I beleive that compaq presario's hardware prevents it from running windows xp. so i'm going to assume your using an older model of windows. sometimes computer companies will stick the windows cd key on the case itself. If you can find this, and confirm which version of windows you have I think i can walk you through how to reformat even though you've lost your cd.
also if you have some kind of technical support id tag on your computer, if you call up compaq, give them your technical support id number, they can confirm that you purchased the computer, and tell you your cd key and even send you another copy of the reformat cd.