Multi-monitor media player mayhem

K heres the deal. Win XP Pro and Power DVD/Windows media player 9. ATI radeon 9800pro grpahics card, monitor as primary, TV as secondar on s-video out. Films dont sho up when played on the TV. Thats mpg and avi played through windows media player and DVDs played through Power DVD. Now this sucks because I ahve to wtach films on my lil 17inch montior and i ahve a fat TV connected and it wont work. What am I doing wrong