Do a Google for "begin2search""removal" and look for something by MajorGeeks
You've got spyware/scumware/adware. They'll be able to tell you what to do better than what we can. You'll probably need to DL a prog called Hijack This to report a log so they can help you, but that's what I had to do.
Spybot may remove it for you as well, but do the Google search first. After you've got it removed, DL Spybot (along with its plug-ins for home page hijackers and another one I can't remember) and Ad Aware and run 'em periodically.