I used to have a slightly similar problem. Not the Virus problem, but the re-install of Firefox. The solution for this in the future would be for you to install and use FEBE Firefox Environment Backup Extension so you can fully back-up your settings, and other Addons, and Themes etc. that were within your FEBE backed up profile, so you can do the re-install of Firefox and then restore your saved profile that encompasses all of or most of what you presently don't want to loose. You could still do a FULL PROFILE FEBE, and re-install Firefox, and do a FULL PROFILE RESTORE, and if you might no longer have a virus problem after the restore. If so, your in good shape. I would find and run a good quality Anti-Virus scan, and if you wish to try to catch what you might have missed with the new scan I also suggest from www.IOBit.com that you add 2 programs that look to be better at catching problems than most other scan and repair utilities. The programs I suggest you add are called Advanced System Care - presently is version 5, and IOBit Malware Fighter, and one other. Their super powerful Smart Defrag that is faster than most Defrag programs and their is only one other Defrag program that comes close to it's power, and that is Diskepper, and you get Smart Defrag for free, and it's better, and faster than the others in my opinion. ASC Advanced System Care will clean your system and make it run faster specially if you have noticed it is slowing down for one reason or another , and it will do this with less resources than the other programs that you may already be using. The only thing they lack at present is an Anti-Virus portion which would add much more value to the already super programs. Good Luck. Let me know what you think after trying the noted programs. You should be very satisfied of the results.

So my settings and bookmarks are toast for now, right? And, do I un-install Firefox and re-install it?