MS Vista update and .MOV files issue

Hi. After a Tuesday MS Vista update a few months ago, I can no longer play .mov files as before using any player and the movie I was making using MS Live Movie Maker has crashed (some files play in QuickTime without sound).

When using existing .mov files or importing new .mov files, it seems the operating system is changing them to .MOV (caps) extension.

The Nikon View NX2 software that came with my new camera will import the movie files from the camera but I cannot burn them to a DVD.

I've tried downloading all the codec software I can find with no luck.

Any ideas are appreciated.

Thanks.

David D.