Alright so I was testing out Avira Phantom VPN and installed it, which included the Avira Connect app and the Avira Browser Security plugin. Then I restarted Firefox and it started working slow as hell and consuming way too much CPU, 10-25% when idle. It's literally unusable at the moment. I tried rebooting my computer, didn't fix it. Uninstalled all Avira software, still slow and consuming too much CPU. Started Firefox in Safe Mode where it works fine, and removed the Avira plugin, nothing. Then I disabled all the plugins, no changes, still slow. Then I uninstalled Firefox and reinstalled it, no effect. Ran Firefox in Safe Mode again and removed the "content-prefs.sqlite" file incase it was corrupt. Nothing. In Safe Mode I tried to Refresh Firefox, it had no effect. I uninstalled it again, and ran CCleaner to clear out any temporary files and registry entries that might be causing problems. Reinstalled it as 64-bit instead of the default 32-it, and I'm still having the same problems. Any suggestions?