hi, I am new to win 7. I just install a trial version of win 7 professional x64, and I download a kmplayer 1431 which works well. However, I heard that win 7 ultimate x64 is currently the best among win7 series, so I install win 7 ultimate x64 on my new mac book pro. Terrible things now happen. The kmplayer, no matter 1431, 1435, or 1437, all fail. I can play a mkv file but only sound are heard. Other format such as avi, rmvb totally cannot be played. When I tried to open these file, a window prompt out saying that "no combination of filter render for this stream"... Have any body came into this problem? How can I solve it?