Having Adobe Flash Enabled caused Firefox to Hang, and then to "Not Respond".
I Have the Following:
Adobe Flash 11.6.602.171
Windows 7 Home Premium 64 Bit SP1
After I first install a new version of Adobe Flash, everything works perfectly.
If I shut down my computer & start it up again maybe 10 minutes later, I will START having a problem.
I Click on my Firefox Icon.
Then I click on one of my bookmarks, like for Tucson Weather ( at www.weather.com ).
While Tucson Weather is "transferring data' or "waiting" or "connecting" the small blue indicator that spins to indicate that the computer is working to get the requested page loaded freezes & stops spinning.
Now, If I click any where on the page including the scroll bar, the page becomes dim & a very light color, white the cursor resembles an hour glass. This only lasts a minute or so.
If I click on the "X" to close the window, either nothing happens, or I get a message that Firefox is not responding, & do I want Windows to close the page. I have Windows close page.
Next I return to Firefox, disable Adobe Flash, & Firefox now works perfectly - Only Videos at You Tube are mostly not possible. I have had this problem since at least last September.