Anonymous
Favorite Answer
Get 'Spybot' it's free and it can protect you against browser hijackers. http://www.spybot.info/
SMarT
Control Panel > Internet Options > in General tab > specify your home page.
I hope your browser is not hijacked in that case you will have to use either Microsoft's Windows Defender or Spybor Search & Destroy to clean the system (you may also use any other similar software that cleans spyware from system).
Hope that does it all!
PS: You can download Spybot S&D from:
http://www.safer-networking.net/
And Lavasoft Ad-aware remover from:
http://www.lavasoftusa.com/