Yep, drivers are the cause of this issue. Since your running windows 7 drivers are a even bigger suspect. When I ran windows 7 for a short bit I had the same issue with my drivers, but by installing the vista drivers over the windows 7 drivers it fixed that. But some vista drivers might cause more instability then fixing stuff when on windows 7. You might want to see if theyve pushed out a newer windows 7 driver.