FireFox problem

Everytime I click on the FF Icon the page begins to load then freezes. At the top of the screen it says FF Not Responding. My IE7 works but it wont let me get on a certain website to chat live. That website uses Flash chat. Is there a way I can fix FF so that it loads completely and I dont get the Not Responding thing again? Or is there some thing I can do to fix IE7 so that it lets me enter live chat on that website? I have Windows XP. Would down grading to IE6 solve the problem that I have with IE7? Should I download Opera instead if FF and IE7 are giving me problems?