I have XP SP2 in my system. Recently it was infected by a root kit virus. After every efforts failed, I reinstalled the OS. Now the system is very fast. Unfortunately, it freezes after sometime. I had reinstalled the OS manay many times in the past. But this problem had never occured. Now I did a OS repair also. But it didn't help. After about 10 minutes the system freezes and the only thing that works is the mouse. When this happens I reboot the system.