Is it possible to connect a dial-up computer to Comcast Internet via a laptop?

I have an old HP Pavilion 533w desktop computer. It has a dial-up port and I think an ethernet port (Marked as one, I think... but an ethernet cable doesn't fit.) I have my laptop set so other devices can connect to the internet through it's connection. My laptop has an ethernet port, which is being used by an Xbox 360, and a Dial-Up port. Is this possible?