Okay, I know its not the DVD and CPU usage is < 40% so I know thats not it. Installed is WMP11 and Nero 6 suite. Legal versions of both on XP Home SP3. GeForce 6800 is the GPU The DVD plays fine sometimes, sometimes it plays choppy and has slow downs/speed ups up to the point where you cant understand what they're saying and its unwatchable. I mean a slowdown then speed up in a matter of a few seconds, like it falls behind with playing the DVD and catches up quickly, and then repeats. Sometimes it says theres a decoder/driver/region problem. And sometimes ti says the DVD is not compatible with the player b/c of the wrong region. I've checked the region and its fine. Latest firmware for the DVD drive, latest nvidia GPU firmware installed. UDMA Mode 2 is enabled. All DVD playback programs I've tried (at least 3) don't work. And i'd like to figure it out in WMP11 because before my reformat a few months ago it used to work fine. Also, I have the same problem on a laptop w/ XP meida center SP3 with PowerDVD and WMP11 installed and K-lite codec pack. I've tried various codec packages from download.com, no difference. On another XPH SP3 with WMP11 I have NO issues, so I know those two alone probably aren't the entire cause of the problem.