RAW thumnail problem - Windows 7

So I am not sure what is going on here. I download the RAW files from my 5d2 and when I go to windows explorer some of the RAW files have thumbnails while others have the Windows Live Photo Gallery thumbnail. They are both CR2 files from my 5d2. Why can't I see all of them in windows explorer?

http://farm7.static.fl​ickr.com …84205179_925445​6905_o.jpg

Hmm, does this happen with all your folders?

I don't know. Of course the "codec" for this was an add-on from Microsoft -- I don't know how reliable it is, you may want to check with MS?

Most are usually the Windows Live Photo Icon but somehow end up as a visible thumbnail. Not sure how this happens.

UPDATE - managed to get this resolved. Looks like it was a codec issue. I reinstalled the Microsoft amd64 codecs and now can view all thumbnails.

Ah, well, good for you! But yeah, it will take time to initially render thumbnails, and in the meantime that dorky icon will show up. But once it does it to a directly, I believe the thumbnails "stick".