Connect the LJ4 to the router. Run a config page to see the IP address. As an aside, can both PCs open a browser window?

Go to control panel/printer and faxes/add printer. Select local printer attached to this computer. Next, The pull down screen should show LPT1. Click on the arrow and you should see the ip address for the LJ4.
Actually, you should see the Printer listed under printers and faxes before you even get to the add printer wizard