sounds more like a problem with your computer than the game.

run a virus, malware check. check if your pc parts aren't overheating (you can do this with speedfan) check how much space you have left on your hdd. go to task manager (ctrl+alt+delete) and check if there are some annoying programs like JAVA UPDATER or ADOBE ACROBAT UPDATER NR 85R54353454 or SweetIM or RunescapeHacks.exe murdering your cpu and turn them off. If you do find that annoying programs start up with windows press windows key + R and run msconfig. from there you should be able to control what programs boot up with windows and turn them off.

also check if your computer was made this millennium.

That was funny.
Aside from the issue being a deep rooted virus everything else checks out fine. I don't think it's a problem with my system because anything else I load up runs fine.

Check your set launch options in your Fortress Forever Steam properties. I had a problem with freezing with setting my heapsize too big. The command should only take up about half your system memory, so if you have 1gb ram, do 512000.

If that's not it, do what moosh suggested and check system processes to make sure no asshole applications are eating up your CPU or Memory.

And of course, if all else fails, you could try reinstalling FF.

I found out what was wrong. The was an executable program named relevantknowledge that was not showing in my virus/malware scan. It was an ad generator for webpages, but something about it was clashing with FF. I went into safemode and deleted it, and FF is running fine now.

cool, glad you could get it fixed.

Smoke, next time post something like this in the tech support system.