most routers can connect via cables usb and ethernet and the wireless. You have obviously connected via a cable to one pc and all is well. The other pc must have either an rj45 socket to connect an ethernet cable from it to the router or a wireless device. Two types of wireless device are available a pci card that gets fitted into a spare slot on the motherboard or a usb dongle that plugs into any usb slot. The usb dongle is the easiest method. When you buy one it will come with a cd to install and you have to follow the instructions for wireless that should have come with the router.