I am unable to open a new tab in Firefox 16.0.2 - clicking the + does noting and the "New Tab" option is greyed out.

Hello JonnieW check it in [https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode#os=win8&browser=fx16 Safe Mode], in Safe Mode window select "'''''Start in Safe Mode'''''" and see if this happen again, '''if not''' see: [https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems#os=win8&browser=fx16 Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems] thank you Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.