Once you get your browser back under control please make sure you are running some form of anti-spyware tool so that it stays under your control.
MS Anti-spyware and spybot S&D are both useful tools that will clean your PC of spyware but can also help to pro-actively protect you from further problems.
Spywareblaster, spywareguard and Ad-aware are also on my list of spyware protection tools.
MS Anti-spyware
Spybot S&D
Adaware
Spyware Blaster
Spyware Guard