Can't view M2T and certain DivX files in WMP11, but CAN in VLC

I have a bunch of DivX (AVI) files and HDV (M2T) files that I could view before, no problem.

I re-formatted my system and installed all the same things I usually do. All Windows XP updates, WMP11, etc. And the following codecs.

DivX
XviD
3ivx

Now... I can view all my files in VLC, but when I try with WMP11, none of the M2T’s load at all, and some of the AVI’s only load partially, no audio, or lockup.

Any ideas what’s going on here?