my computer in the lab has been used without my permission by a labmate He told people that he knew about computer OS, he partitioned the computer discs into many rooms. There is a drive room for my Windows XP 2003 Service Park 2. He installed some OS I don't know what to call on the other free room drive. Sadly enough, he succeeded. But now when I log into my XP account, the screen becomes darker than before (50Hertz is the rate for refresh), it was 60 before hte install, I know it! Help me please.