Play a movie in bsplayer.
Right click, filter properties: which names are listed there?
Download Sisoftware Sandra 2003 @
http://www.sisoftware.demon.co.uk/sandra/, install, run DirectX diagnostic module, scroll down to the bottom: what does it tell about available overlay color spaces?
Did you install latest graphic card driver for the appropiate OS (XP?, W2K?)?
Did you download the movies from the net? Which resolution do they have?