Hold down the Shift key when starting Firefox and start in Safe mode, does it work there?

If it works in safe mode, you need to disable hardware acceleration and or disable a addon.

for more see: Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

If starting in Firefox Safe Mode works then you can try to disable hardware acceleration.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

yes it does :D