hey guys I have 2 computers both running windows 7 RC

One is a AMD Athlon 3500+ with 2 gig of ram whilst other is a dual core 5000 with 2 gigs of ram and a geforce 9400gt card.

My first one only ever watches tv through xbox 360 as an extender but after awhile (1 or 2 hours) they sound goes out of sync and i have to reboot the xbox to get it back to normal.

Same thing happens with the computer running by itself both in windows media centre.

Both computers have a hauppauge 2200 tv card

How do i fix this?