This may not be the solution you are looking for, but is something you should run on your system from time to time to just keep it clean running and fast.
Download and run the program "HijackThis"
Start the program, select system scan. You will have a list of all the stuff that is currently being loaded and running on your system.
Mark and remove any lines that have references to either or both, FireFox and SupplyScan. Restart your system and the problem you are having will probably be gone.
If you run HijackThis and have more than about 5 or 6 items listed, you have things running that don't need to be there and are slowing down your system.
This is really a great tool that I have used for years. Take time to learn how to use HijackThis, it has lots of information about it's use, and is a safe program to run.
Hope this helps,
George