I just bought a new graphics card (Sapphire Atlantis Radeon 9600PRO 256Mb). Ever since, I have been experiencing problems with video playback. Video playback works perfectly fine if I just watch it from the start, but whenever I try to skip to a different part of the video, the playback just freezes. The computer still works fine and I can simply press stop and start watching again with no problems, but it is quite annoying that I can't skip. If I skip enough times, it eventually works, but often with no sound... Any suggestions?