My missus had the same problem when she signed up with Tiscali. The software greys out the option in IE Tools/Options to specify your home page. It took the genius of Oulli the Younger to solve that one. Do you have "SpywareBlaster"? If not, get it. Under Tools/Misc IE Settings you will find a tick box marked "Disable the IE Home Page settings in the Internet Tools Control Panel". My money says that it will be ticked. Untick it - then you can reset your home page in IE Tools/Options. Job done.
As a bonus, on the same page of SpywareBlaster, you can re-write the lettering that appears on the IE title bar. Something rude perhaps.