Video Problems In Vista?

ok i just upgraded to vista from xp, and i just tried to watch a movie i downloaded using WMP using the k-light audio & video codec pack, and this yellow bar flickers in the middle of the video, it does that with all my movies, the colors very every now and then, and then on some movies it doesn't have a bar, instead its across the bottom - heres a pic i took showing you what im talking about - http://img692.imageshack.us/img692/5958/15444726.jpg