Cisco Pix 501 Firewall (Help is MUCH APPPRECIATED)

I’m not a network specialist but we have a Cisco Soho router connected to Cisco Pix 501 firewall. Someone previosuly set it up for us and I can’t get hold of him now.
I would like to open some ports on the cisco but I don’t have any clue how to do that nor do we have the software ( I think) becuase I check the win 2000 server.

How can I open some ports?

Also, I tried to over pass the firewall by connecting the wire from the router directly into the pc (server box) but the internet connection doesn’t work! Any ideas why?

Many thanks