It doesn't have to be Firefox. I use Mozilla 1.7 ~ basically the same thing without all the bells and whistles.
It works well to open it when IE starts giving you problems.
I have the same problems with PMs locking my IE browser up
(it has to do with the ads on the site),
so when IE starts doing that I switch to Mozilla.
http://www.mozilla.org/products/mozilla1.x/)