Actually, I had a similar problem...
There is this "option" that opens when you visit sites that have this:

A video codec needs to be downloaded before you can view a video.
HOWEVER, you can HEAR the sound of it though...
If you accept, it's a trojan that goes by "Zlob" (zlob.trojan).

When I accidentally got this infection and tried using LW, I too had that issue.
Since Trojans love to target backdoor programs, it hit's LW too.
Just run virus scans/removers, and then reinstall any system files the computer needs, and THEN delete and redownload LW. It should work beautifully again.