Even the first gen 6xxx series support pure video (code named VP1), HD videos for 7600GT is a piece of cake, please do not spread FUD if you do not know what you are suggesting.
Check the wiki link I listed. VP1 supports full acceleration for mpeg2 (what used to be standard codec for DVD) but limited h264 or VC-1 acceleration (Blu ray, modern downloads). Thats why I suggested 3rd Gen+. If FUD was my intention, I would have asked him to get the latest and greatest, not something thats 3 year old. And against a documented proof of what i am saying, we have your word, so much for FUD. Can you try and decode "killa sampla" (google it) and come back and say if it works on your 7600GT.