Eliminated All The Games Music - Asking Password To Start

A friend has windows XP, which he has been using as an offline thing to just do correspondence etc. He is not internet wise, and has not used internet since his son emigrated to the UK in March.. I was helping him set up internet and outlook express as he has just signed up with a wireless internet connection. We were doing a disk clean up, had eliminated all the games, music and adware files that his son had on the PC and had downloaded AVG (he had no virus protection at all and I insisted before he started using the internet we download some form of protection) and were doing a virus check ( 1900 files, over 200 virused with mainly win32/parite but a lot of trojan horses too!!!)