Windows Experience freezes @ "tuning windows media decoding"

I've seen it happen before, not much of an issue really. Just don't run it. It does not affect anything else on the computer. Just an issue with how MS runs their video card tests. You can poke around the MS updates site to see if there is a fix. Easier to just not run the thing.

If you want to find out how fast your video card is, run 3DMark or something similar.