Rating videos and adding tags in windows 7

I can't do either.

Videos are .avi and .mkv. Do they need to be .wmv in order to add tags and a rating, or am I missing something?

Still curious

Use Griffith. It's a complete video db software with db import/export backup capabilities including cover art.
http://www.griffith.cc/
Lately I have had only the issue of when it pulls data off the net, the title's year of release does not reflect the actual (says1899). Other than that, it's crossplatform, free, and the best I know of. I use it to keep track of my now 400+ titles.