I have a computer that I would like to do a clean install on because when I shut it down I get a stop:C000021a logon error message. It says that the system had to shut down and the only thing I can do then is turn the power off to restart it. I did try to reinstall xp and at the begining it said there was another logon program that would not allow windows logon to work. It said I should remove this but I have no idea where or what it is. If I do a fomat of the hard drive will that take care of it ? Is there some place to get easy to follow intruction to wipe the drive and reinstall XP? I do not need to save anything that is on this drive, it is only used for my son to play games and browse the internet.