Your browser has been "captured" aka "hi-jacked."

Lots of "techies" will provide you with a path to freedom.

Forget the MC's wannabe Firefoxers - That browser can also be captured by the likes of "I-Search"

Setup a defence system....start with Gibson Research Center and probe your ports....then explore lavasoft, ZoneAlarm, and spy-bot. However, be VERY cautious of Google "links" which might lead you to mal-ware (malicous software) posing as a solution to your problem.....but instead adding more trojans, loggers, or popups to your machine.

Sincerely,
Gargoyle