issues when playing video

[Overture]

well i just built my new rig, its up and running perfectly fine now. the last and only problem though is when i play videos, theres a glitchy looking line that goes horizontally across the middle of my video whenever theres alot of movement or color changes in the video(which is alot in amvs). i have no idea what it is or what could be causing it but i would assume it has something to do with my video card. i installed its software so maybe i have to configure it a certain way or something? any suggestions? its really distracting when i watch anything so i need to get rid of it b4 i go any more crazy:{