I'm pretti nooby to vegas. Tho i've used 6.0 before and it worked fine

I just recently installed 7.0 and when i open an anime/video with vegas 7.0

The sound shows up but the video doesn't come out anymore.

Any help would be apprecaited.

I tried uninstall codec and reinstall codes and all..

I can play those videos fine in my WMP... but vegas doesn't show ... Thx a lot