someone deleted my windows xp from my advent 1770 laptop. it came up a black screen saying there was an error and that id no windows.. so i tried loading windows millennium on to it. a really old disk it worked fine until it asked me for the product key which i cant find and since it was never on the laptop or any other comp in the house so I've absolutely no way of getting the key any way i can go back to the start like deleting it from my laptop to try again with a cd i have the key off please please help me