You could see if it is any of the Firefox-Extensions witj Firefox 2.x that is the trouble.
Go to start programs, Firefox, Firefox-(Safe Mode) and then see what happens. If all is ok then I bet it is one of the Firefox-Extensions so then your need to get out of safe mode so close Firefox down and open it up again and disable Firefox-Extensions one at a time or all of them and turn them back on one at a time checking web site after each change.