Hi, i just got an inspiron 9300 with a 6800go, running XP with SP2 on it

the problem is that everytime i open a video file, using quicktime, WMP, and divx player..the same thing happens with all 3

the screen gets lines all over it and the resolution goes really large, almost like it zooms in. the video still plays though.
the only way i can get rid of it is by putting my computer in standby and logging in again, or by shutting down completely
sometimes when this happens, the computer just locks up

i have the latest WMP and updates and codecs, no viruses and i've defraged 2 days ago

any help would be appreciated
thanks