Not knowing your browser or operating system makes such questions more challenging than necessary. If you know the IP address of your preferred search engine, enter that and you should end up at the desired site. For example, if I enter http://64.233.161.104/ it gets me to the US google site whereas entering www.google.com gets me to the VN-specific google site every time.
why not try downloading firefox. its free and i really find it to be the best search engine. perhaps the instalation will help remove the problem as well as give you a better searcher. it is really that good in my opinion.
U have to clean your cookies in your browser!
How to do this: Tools->Internet Options->Delete cookies...
It's must help you :)
If no then check your computer for virus :)
Good Luck!
I think your PC has been infected. Try downloading some FREE spyware programs or use Windows Defendar to scan and also have a full system scan from ur anti-virus. From what u describe, it is some sort of virus like Spyware or Trojan horse...it has nothing to do with ur system or browser...cheers!