I have had this problem since I got the laptop last December. Video in full screen is erratic. In scenes where there is little motion there is no problem (or the problem exists but is not visible). The problem manifests as a horizontal "tear" about two inches down from the top. In order to capture the problem I had to record a video with a digital camera. I've attached a screen snap of a video frame. My guess is that I am seeing the top two inches of one frame and the rest of another frame. The three players (all current version) display the same problem. I've tried vlc media player, DivX player and Windows Media Player. All of my driver software is up to date. I built a Linux LiveCD on an external drive and boot to that. Try as I might, I could not get the problem to show up in Linux. I've also run a full slate of diagnostics. That plus the Linux success has convinced me it is not a hardware problem.
It doesn't matter if I am playing a low quality (320x240), medium (620x480) or high quality (1280x720) video.
Any suggestions on how to track this down would be appreciated.