This usually happens when security software prevents the new version from running. Try removing any rules for Firefox from your firewall and similar software, then either create the rule manually or allow Firefox access when prompted.

Also see

• Firefox won't start - find solutions

tanks for your help but unfortunatly the problema isnt from the security software. to check i even uninstalled the software..

i cant open the browser anyway..

Can you start Firefox in Safe Mode by holding down the Shift/Options key?

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes