If you start Firefox with the command line firefox.exe -safe-mode Firefox will start without any extensions or themes. As you can see adding a command line argument to the program's executable ...

Type firefox.exe - P in the Run box of Windows. Click the Create Profile button without making any modifications to your existing profile (which is normally called "default") ...

If you must have two versions of Firefox running concurrently there's a very basic workaround that will allow you to run multiple instances and versions of Mozilla's ...

Both Chrome and Firefox have the ability to take screenshots of web sites directly from the command line. This allows you to create scripts or scheduled tasks that automatically take screenshots ...