Hi, I just got a new computer (HP Pavillion DV6880) with Vista 32-bit. One of the first softwares that I've installed was QuickTime 7.5(861). I tried to view some trailers in the Apple site and got only sound and no video (a black screen).Another thing is that when I've entered to a movie site that has HD trailers I couldn't see the HD buttons that operate the trailers (480p, 720p etc. icons) all I've got are only black boxes (I can click on the boxes and view the HD trailers). The same happened in http://www.apple.com/quicktime/troubleshooting/ site, I didn't see a broken icon or something like that, I only saw those black boxes. I should mention that when I right-click on the black screen/box I can see the Quicktime options table, and when I download the trailer to my computer I have no problem to view it (video and audio) with QuickTime Player. First I've tried to reinstall the software, after that to install some extra codecs, and also tried to enable "safe mode (GDI only)" or to disable the "Direct3D video acceleration" in the advance screen, but nothing seems to work (I even tried to delete the QTPlugin.ocx). If someone had this kind of a problem or have any idea on how to fix it, please write me an answer. Thanks.
OK, After a while, I found a kind of an answer to my own question. I've tried to use Firefox instead of Internet Explorer 7, and everything worked fine, sound and video. So, maybe this can give someone a bit of a clue on how to solve this mysterious problem.