my friend got a virus probably and his windows crashed. he starts it up and then it shuts down. im recalling this from memory but i beleive im pretty correct. i dont think their is a blue screen of death. my question is how can he find out what OS he was using. because he talked to a friend or some tech person and was told he needs to reinstall the OS from the disc. which he doesnt have so he doesnt know which one to buy. also if he has xp home would it mess up the comp if he installed xp pro or vice a versa? sry im new to this not forums but this site if this is the wrong thread sry. also ive been told to watch my grammar and capitalize since i used bad typing like in aim before so im trying to spell stuff right. if you need anymore info ill try to get all i can. and this is a desk top. i dont know the make or model or anything not that it matter since its kinda a virus/software kinda thing. anyway thats all thx for any help.