Troubleshooting Firefox By Running In Compatibility Mode
Did running Firefox in safe mode didn’t help you and clearing cache didn’t improve any conditions? Well, there is one more way out which might help your Firefox run smoothly. Many times changing the compatibility of Firefox might help your Firefox face least problems.
Right click on Firefox shortcut and click on properties. Set compatibility mode back to Windows 2000. This might actually solve your problems. Try it!
If nothing works then creating new profile might help out.

I’ve looked at 6 different firefox.exe’s on my hard drive, and in the Properties of each file not one has any mention of compatibility mode. I’ve also checked the Properties of the shortcuts…still nothing. Where can I find this?
I said right click on the firefox shortcut..I tried just now and it worked..