windows 7 mkv thumbnail generation.
 

so i've been one windows 7 x64 for a while now, and i havent had mkv thumbnail generation for a bit now, and i've been dealing with it, or so i thought. im starting to get irritated because ive been so use to having them when i used windows xp, i was wondering if anyone has a solution to this, i would appreciated it so much if you would share your experience.
TIA