Using the most up to date Firefox (16.0.2), and Adobe Flash. Whenever I go to any youtube video or flash video on another page, Firefox starts the video, but only plays the audio, and then when I make any click on anywhere within Firefox, it gets completely stuck. It freezes and the only way to get it to close is to go to task manager.
I restarted in Safe Mode and it did the same thing.
Windows 7 64 bit.