did you solve your problem?
I had a same/similar problem.
Finally completely cleared it up today.
Finally, I did. Uninstalled Firefox. Installed Spybot/Antivirus. Had a bad time running Spybot (”time remaining for scan , 5423 minutes”). Had to contact Spybot and get them to help me run it (it has to be run in safe mode). Found 25 problems. Fixed them. Reinstalled Firefox. Runs well now, But was amazed at how many hundred/thousand crap entries were in my computer, 99% of them spam.