QuickTime Plays Audio But No Video

Question

For the past few days everytime I play an mpg or mov on my QuickTime Player (7.3), I hear the audio but instead of seeing any video, there's only the native aqua gray screen. This not only happens with downloaded mpgs or movs on the Internet, which
plays fine in whatever browser I'm using, but also with mov files I've made myself with Final Cut Pro.
I've already researched similar problems within this forum from the past few months and I've tried various suggested solutions, like trashing the QuickTime preferences, restarting, repairing permissions, but nothing has changed. I've also gone into QuickTime preferences>advanced>mime settings, checked the "video" box, clicked okay, and restarted, but when I drag a mov file onto the QuickTime icon in my dock, the SAME THING happens, audio without video.
This hasn't affected anything within FCP, but I can't see any of my files in QuickTime. The only thing I did lately was install a third party program to change the look of my iTunes interface, but I completely trashed my iTunes program, all related files, including my music library, and reinstalled them from my backup drive, in case that affected QT.
Any ideas?
Jeff

Answer 1

For the past few days everytime I play an mpg or mov on my QuickTime Player (7.3), I hear the audio but instead of seeing any video, there's only the native aqua gray screen. This not only happens with downloaded mpgs or movs on the Internet, which
plays fine in whatever browser I'm using, but also with mov files I've made myself with Final Cut Pro.
I've already researched similar problems within this forum from the past few months and I've tried various suggested solutions, like trashing the QuickTime preferences, restarting, repairing permissions, but nothing has changed. I've also gone into QuickTime preferences>advanced>mime settings, checked the "video" box, clicked okay, and restarted, but when I drag a mov file onto the QuickTime icon in my dock, the SAME THING happens, audio without video.
This hasn't affected anything within FCP, but I can't see any of my files in QuickTime. The only thing I did lately was install a third party program to change the look of my iTunes interface, but I completely trashed my iTunes program, all related files, including my music library, and reinstalled them from my backup drive, in case that affected QT.
Any ideas?
Jeff