Network Cable Unplugged

I'm getting the message that the Network Cable is Unplugged on one of my computes. I get this on both my wireless adapter and and the On Board even when the on board is wired. It's not my router, 3 other computers are connected with no problems, i.e., can connect to the Net as well as with computers on the network. Tried the wireless card in different slots, uninstalled and re installed the drivers. There are no conflicts in Device Manager and both the onboard and wireless can be seen in Device Manager, no yellow or red signs. In ipconfig it says that IP Routing Enabled NO and WINS Proxy Enabled NO. Media State Disconnected. Using Windows 2000. Everything was working fine and turned on the computer this AM and had no network connection. Any help would be appreciated. Thanks