I'm trying out the Vegas 7.0 trial before I buy it. I used the trial last week to edit some audio just fine. I then installed the 7.0b upgrade over top of it. Now, when I click on the Audio Track FX, the Audio Plug-in dialog box comes up all black - can't see anything. When I click on the X to close it, I can briefly see what's supposed to be there before the dialog closes. I tried uninstalling version 7, then re-installing the Trial 7.0a, but the problem persists. Any suggestions?