InformAction Forums

I was watching a video on Youtube when suddenly Firefox crashed. I tried to reopen Firefox but a message appeared "...that one instance of Firefox is already running". So I opened the Task Manager. The moment i did that, three unknown programs started running. They were suspicious, so I closed them. I didn't find firefox.exe in the Processes. Then I ran Firefox again and it opened. I quickly noticed that the NoScript icon was gone. When I checked the Firefox Extensions, all installed extensions were gone but the CompareItApplic which wasn't there before (the date of installation was the day when all of this accured). I removed and uninstalled CompareItApplic from Firefox Extensions and uninstalled it from Windows 7 control panel. I cleared all history and restarted Firefox from Troubleshooting information menu. Then I ran Spybot which didn't find anything noticeable and then Malwarebytes Anti-Malware which didn't find anything either. Now everthing seems normal. The only problem is that I have to reinstall all the extensions to the Firefox and I lost the Noscript whitelist.

Did anyone have this issue?

Your system has been infected with malware, NoScript being removed is the least of your problems.

Please scan your system for malware using both your antivirus and a tool like Malwarebytes Anti-Malware (the free version will do). If that does not get it try also AdwCleaner.

S/he already tried Malwarebytes. But I agree, this sounds like malware infection. If all seems quiet again, then chances are that the malware has gone to ground and it's time for a system reformat + restore.