windows problem playing 1080p videos?

I am running windows on a new Dell Precision m3800 laptop. I am having problems running videos in Quicktime in 1080p and 720p. When running the QT app, I get a transparent display area with no sound though the time bar at the bottom is moving. When I try to run a 1080p and 720p trailer in any browser I get a black screen and sound only. Has anyone encounter this before? lj