Yet again, the problem is nothing to do with Firefox. You've still got a nasty trojan on your PC. (The trojan identifies your browser and adds' Mozilla Firefox' onto the end of its false messages. If you were using another browser you'd see the name of that browser added onto the messages).
I'm surprised that Malwarebyte's AntiMalware can't detect and fix the problem.There are dozens of websites which claim that their products will do the job for you but they all require payment.
If I had the problem I'd remove the files (and edit the registry) manually but it's not a job for the feint-hearted! The instructions start at 'Remove the processes' here:
http://www.id-theftprotect.com/news.php?news_i d=553
If you intend to try that method please make sure that you know how to back up your registry (and how to use the back-up file if things go wrong):
http://support.microsoft.com/kb/322756
If in doubt, get a professional to do the job for you!!!!!!!
Chris