Well, you could tell us what kind of video card you're using. Then we can figure out if it's a driver problem (my guess).
Do an lspci and paste the video lines in here for us.
Also, how are you running BackTrack? LiveCD/LiveUSB or did you install?
After that information's out, we can give you a hand. Other than that, welcome to BackTrack, and read THIS THREAD.


