To take a screenshot, press the Print Screen button (Prt Sc or similar) near the top of your keyboard.
Then paste it into an image program, such as Paint, or anything really.
To make IE the default browser (which wouldn't affect much by the way) go to Tools --> internet options --> programs, and it's in there.
It is for IE7 anyway, I think it's pretty much the same for IE6?
Do correct me if I'm wrong though.
If you've got Firefox installed and working, good for you.
I bet you won't want to go back soon.