How do I fix computer freezing up?

My computer freezes, usually when I am playing Pogo, and I have to power off and on again. I am unable to move the cursor or anything, and the sound goes crazy like a skipping record. Internet Explorer seems to hang a lot also. I am running XP 2002 and I recently reinstalled the video drivers, otherwise have not downloaded anything. I have AVG anti virus which runs daily. Help?