Is it possible to reformat a computer without the disk? I have an HP computer my OS is XP. Recently got a virus that is hellbent on installing shit on my computer. I know what file it is because of this program I have called game booster that closes unnecessary programs and there was a recent addition to the list that wasn't there yesterday. Unfortunately I can't just delete the file because the program seems to always be running...Pretty sure I need to reformat.