4850 problems with Vsync

Hello, has small or, nevertheless, big? Problem.. with my new PC. Having in plays, if I switch off the Vsync. Falls, the monitor goes on Standby and the calculator does not react any more. Do I the Vsync again, if everything runs without problems., Unfortunately, I cannot explain myself why this is so. Hence, my Thread here. Having up to now only two plays tested, Left 4 Dead and World of Warcraft. There these mistakes existed in each case. The drivers of Graka are the most topical of ATI. system

Phenom 940
gigabyte UD4
4 GB of OCZ 1066
Samsung 320gb
Asus in 4850 and this hangs on Samsung 2433bw. OS: Vista 32bit

Hoping to me somebody can help. Thank you schonmal

Spongy