Same happened to me a while ago (browser hacked).
Unnessary Step
I was in a bad mood so I verbally attacked the website owner after tracking
DNS details and then threatened action under the Data Protection Act 1988
How I Fixed It (Best not use the first step above)
Clear IE7 Browsing History From the Command Line :: the How-To Geek
Try using command prompt, it rips everything out without even running your browser to reset settings, etc.
Cheers,
B