Right i dont know if i understand the problem 100% But it sounds like a file accosiation problem...

It sounds like..
The Game starts..
Tries to play opening vid...
and goes POOF.
Back at desktop.

If thats right. I would start by making sure Windows media player is default player for file types STW uses.

Also.
If you have a Webcam stuck to your pc. "logitech expeshialy" Dissconnect it. and then try again.