14.04 after upgrade freezes with fire fox

[Linda]

Thank you for all the suggestions for how to solve the fire 
fox freezing the computer issues.
Just wanted to post and say that the cause of the computer 
freezing was definitely the xul-ext-ubufox package.
I installed from Mozilla and started and it disabled this 
addon and ran fine. Turn it back on it freezes the computer.
It probably is because I run Ubuntu 14.04 with gnome 
flashback (Metacity) not unity and compriz
I removed the repositry version of firefox and the 
xul-ext-ubufox package and am using firefox 33.1.1 off their 
website .
Ran it all day without a problem.
             Thanks
              Linda