User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:37.0) Gecko/20100101 Firefox/37.0 Build ID: 20150326190726 Steps to reproduce: Allowed Firefox to update. Then could not access internet via wireless through any app including ie. Connected via wire and then uninstalled Firefox and downloaded and installed new version. Worked OK on previous update but the current update failed this time and I had to restore older point on 8.1 to get back to old version. Disabling Norton 360 did not solve problem. Wireless was reported OK and connected even though I could not access anything. Norton 360 was uptodate and all Windows updates had been installed.
You should use the support board for support requests: https://support.mozilla.org/en-US/questions
This is most likely a Windows Restore issue than a Firefox one.