Do you have any protective software (anti-virus, anti-spyware, firewall,
etc.) that is set to alert you when your home page is changed?
Some types of malware will attempt to change your home page and make it
very difficult, if not impossible, for you to change it back. Therefore,
if you change your home page from what it was at the time the protective
software was installed, the software will ask you to confirm that you do
indeed want your home page to be changed.