A network printer plugs directly into the network via ethernet. and doesn't need to be connected to the PC. The network printer will have an IP address and you can add it to any PC or MAC by searching for network printers.
Based on your description, it doesn't sound like a network printer but a regular printer that is shared on the PC. If that's the case, the next step would be to see if you have any firewalls running? Can you see any shared folders and access file over the network?
I need help setting up a network printer, so here's the layout. I have a pc (xp pro sp2) with a printer connected to it, I also have a macbook pro (wireless internet connection) that I use around the house. On the pc I share the printer and give it a name like officeprinter, when I finish my work on the macbook I try and print to that printer, but it fails to print. I was wondering if anyone could walk me though this, so that i can see the step i missed. Any kind of help would be great.