Sounds like you got some nasty creatures on board Marke. You should follow TwoRails advice and run an AV scan along with an adaware one for good measure. The behavior of your browser is in no way within normal param's.
If you didn't already know, good free progs are
AVG Anti Virus Free Edition and
Spybot Search & Destroy.
Don't be tempted to buy 'better' versions at a price. These free tools are more than adequate, in fact they're very good.