Firefox freezing with Flash sites

Hi,

I have the latest version of FF, 14.0.1 and the latest one for Flash player

11.3.300.268.

Under Vista Business environment.

Each time, I looking for a streaming video from a sites, blogs, and forums. Firefox's freezing and it takes long time for loading the page. Videos freezes a lot.

How can I fix this issue ?

Thanks for your help.