Newb help plz

My Satellite Setup
sony DTV
Hi i have a S0ny DSS satellite and receiver and am completely new to this. I have read about updating firmware through the serial port in the back through my computer...and am wondering if i can have any this the right method? what will this allow me to do? i also have a video capture card in my computer and am wondering if u can pass data through the satellite in port of the receiver to the capture card....or if that is a dumb idea....plz dont laugh at my newb stupiity and newb hel would b great if u can tell me if there is anything i can do w/ what i have got.