TUTORIAL: How to fix Sony Vegas (Black video/No preview) Problem!!!

This is my first tutorial and it is for fixing the ":No preview or Black video" problem in Sony Vegas (should work on either 8 or 9). One easy step for one annoying problem, Re-install quicktime, or at least downgrade it. Here's the link for quicktime 7.55: http://www.oldapps.com/quicktime_player.php?old_quicktime=1 Heres the Older version of Itunes as well: http://www.oldapps.com/itunes.php?old_itunes=53