Some websites illegally modify your registry editor and set their website as default home page, for stop this,
1. Right-click on the Internet Explorer icon on your desktop and select "Properties".
2. In the "Target" box you will see "C:\Program Files\Internet
3. Now by adding the URL of the site to the end of this it overrides any
Homepage setting in internet options:
"C:\Program Files\Internet Explorer\IEXPLORE.EXE" www.google.com