This morning Firefox stopped working for every website I attempted to access. The window shows the "Unable to connect" error. I'm currently using Edge for the Mozilla site help pages. I've tried many of the help article procedures, including: 1) Removed and re-added Firefox in the Windows Defender Firewall settings; 2) Scanned PC for Malware (Webroot SecureAnywhere, CE25.1), no threats detected; 3) Cleared recent history from Firefox. 4) Opened Firefox in Troubleshooting Mode but the problem persists. 5) I've also set the Network settings to "no proxy". Windows settings is set to automatically detect settings Firefox was working last night when I was installing an old version of Quicken 2015 (off-line/non-network installation). What's my next step?