Another word of advice is that when you are presented with installing some questionable software do click yes, do not click no or the "X" to close, these mean yes!!
What I do in XP not sure if it is still utilized in Win 7, is hit Alt-Ctrl-Del then under Application tab select the browser and select "End Task", this will close the browser but be aware that when the browser is restarted the windows/tabs may re-open, close them down quickly!
