Firstly, when you go to
tools > internet options
You cant change the homepage??? Mines running on default settings, and i can change mine.
Sounding from things, your firewall seems to be the issue here, what firewall do you have? also it wouldnt do any harm to run a spyware/adware scan, just in case anythings creeped on the computer and is purposfully getting int he way of things.