chainrings

three like other bikes? Is it possible to upgrade to three chainrings, should i even worry about this, and do you know how this will affect my ride?

I think that might be what is wrong with mine, but I am not sure how to tell. Halp?

I have a pretty nice mountain bike that I took out for a ride in the winter while there was snow on the ground. Unfortunately when I was on my way back the salt truck came around and now I find myself with a rusty chain, chain rings, and a bit on the screw where the pedal enters the crank. I...