I was having problems with firefox a while back. Not with this site though. I eventually found a small program when I went to my add/remove programs in control panel. When i went to remove it, it locked up my computer and would not let me remove it. This is spyware/spamware. I eventually, after trying for a few days decided to reformat and re-install (big pain, lost lots of information) but my computer was fixed. There are sites that put this on your computer so when you are browsing (even if you are not on their site) they get hits and can make more on ad revenue. It's a lot like looking out for squirrels on the race track. They are there, can you avoid them.

You may want to go and uninstall firefox and go and install the latest version of firefox. mozilla.com