Also look for any Service packs which needs to be updated.i had the same problem - just go to Windows update site,it will find what are the updates required for ur PC,select which are for IE and ur problem should get solved until they come up with more service packs
Ofcourse FireFox rocks,but some sites have been written dependent on IE,so that some of their features dont work,for instance if u use icicidirect in Firefox,u cannot select the different tabs - trading,News etc..,so in a way we will be still stuck with IE for somemore time.