I agree with the last comment, it sound like your browser has been hijacked, you need to scan it with any or all of the following;
Spybot search and destroy. http://www.spybot.info/en/download/index.html
Adaware http://www.lavasoft.de/default.shtml.en
Spy-ware doctor http://www.pctools.com/spy-ware-doctor/?ref=downloads
A-squared free. http://www.ieaddons.com/AddOn.aspx?cid=1&scid=63&aid=55979bcc-5b8a-4e2d-8235-849660a4b985
windows defender http://www.microsoft.com/athome/security/spy-ware/software/about/default.mspx
And you could use these two to try and protect your system;
Spy-wareBlaster http://www.javacoolsoftware.com/sbdownload.html
Spyware Guard http://www.javacoolsoftware.com/sgdownload.html
finally here is a free anti-virus program;
Anti-vir (anti-virus) http://www.free-av.com/
And a very useful very safe system cleaner:
CCleaner http://www.filehippo.com/download_ccleaner/
All of the above programs are free, except spyware doctor, which will ask you to register to remove the spyware for you; however, it doe say where the spyware is so if you know enough about computers/software you can remove the spyware manually; ccleaner is good for removing tracking cookies and any spyware in internet temp files, it is also a very good safe reg cleaner and general system cleaner.
I hope any of this info is of use to you or anyone else reading this...
culata,
Rosshi
Rosshi, September 2006