I just got Sony Vegas 09 for my Windows 7 Computer. When I try to drag my videos to the box below to edit it, the sound is the only thing that goes in the timeline box. Ive seen many people on youtube have an issue with a "black screen" but in my case, no black screen shows at all. When I click the video I want to use, it automatically brings only the sound into the timeline. Any ideas on why I cannot see the video nor the black screen? thanks