Hmm, well you say that you get a signal, that you can see it on the track your supposed to record on.. that should mean that the inputs are ok. I assume that you have the record button on the track enabled, and then the big record button on the transport.. after you actually press the big record button you have to press play too!!
But if you have done all this, i can't think of anything right now.
Did you get a DVD with your package (Pro Tools Method One), if you did try watch it, they have som really basic steps one how to set up correctly.
But i'll post something if i come up with anything, i'm gonna be reinstalling windows soon.. see if i can get my mbox working!!