If your Firefox browser is unresponsive or experiencing random crashes, it may be necessary to completely reset your internet browser to its default settings.
How to Reset Firefox to its Default State
Click on the Menu option, and select the blue Help icon located at the bottom of the page:
Select the menu option that reads Restart with Add-ons Disabled:
A small menu will appear, asking you if you would like to Start in Safe Mode or Reset Firefox. Click on the Reset Firefox option:
Follow the onscreen procedure to restore your Firefox to its original settings:
For Other Versions of Firefox:
Windows 7
Click on the Start button, and enter the following command in the Search field:
firefoe -safe-mode
Linux:
Open Terminal and type:
/path/to/firefox/firefox -safe-mode
Mac OS:
Open Terminal and type the below command:
/Applications/Firefox.app/Contents/MacOS/firefox -safe-mode
Photo: 123rom