Ever since I got my new computer up and running, I haven't been able to get Flash working properly on it. It works ok in Internet Explorer (sorta- can't make videos fullscreen), but in FireFox it just won't work right. It will work ok for a couple hours but then when I try to play a flash video it will play for only a few seconds and then pause. Other times it will play the video with no sound. To fix this I have to uninstall flash and reinstall it again. I also can't put videos into fullscreen mode, I can hear the audio then but no video will play. I've unisntalled and reinstalled it several times, that only fixes it temporarily. It's getting very annoying. Help?

They have an uninstaller for Flash:
How to uninstall the Adobe Flash Player plug-in and ActiveX control
The Audio failure is mentioned in their FAQ
Flash Player audio failure on Windows

I would run the uninstaller-- then go into regedit-- and delete any references to Flash-- it is part of Adobe now, so entries could be a sub-folder under Adobe.
Find any folders for flash... just right-click and delete them.
Perhaps run CCleaner's registry scanner for any bits /pieces.... then reboot.
Redownload/reinstall fresh.

That didn't fix it.

Wow... that is strange--but you are running Vista I see. Worked for me under XP.
sorry for my delay-- I'm going to see if i can find some more suggestions.
It may take some time...

Apparently this is a "known issue" in Vista... Microsoft and Adobe are working on it...

This guy found a solution-- it may work... it may not.

The Personal Blog of Jason Dunn Blog Archive Fixing Adobe Flash Problems on Vista

Apparantley there is an issue with ATI drivers for there gfx cards and flash in vista see here> Adobe - Macromedia Flash Player