I usually don't even read threads by you, i figure if you have a problem no way i could even understand it.
however i have a few guesses... (they are probably wrong, sorry)
1. Make sure your settings are adjusted
2. Go to start -> control panel -> display -> settings -> advanced -> refresh frequency
3. Update your video card
4. Did you recently get the sp2?
5. Run around in circles like a chicken with its head cut off (might work never know)
6. Open your hardware device manager and make sure there are not "!" next to the video card.
7. These videos aren't downloaded are they?
8. Make sure they aren't zipped
sorry that wasn't that great...