I used an xp disk I have used many times before this time it was to scratched to read foolishly I loaded it anyways formatting my drive now my computer shows it can not boot due to corrupt or missing files how do I recover previous os with out disc it's an old hp ze400
but I stole the copy myself from an it guy at a local college kinda??? I copied it while he was out of the office can they tell the difference between a clone and the original copy???