When you try to set an IP address on a NIC, you receive:
The IP address XXX.XXX.XXX.XXX you have entered for this network adapter is already assigned to another adapter <Name of adapter>.
<Name of adapter> is hidden from the network and Dial-up Connections folder because it is not physically in the computer or is a legacy adapter that is not working. If the same address is assigned to both adapters and they become active, only one of them will use this address. This may result in incorrect system configuration. Do you want to enter a different IP address for this adapter in the list of IP addresses in the advanced dialog box?
NOTE: XXX.XXX.XXX.XXX is the IP address that you are trying to set. <Name of adapter> is the name of the network adapter that is in the registry but hidden in Device Manager.
If you press Yes, you can change the IP address. If you press No, XXX.XXX.XXX.XXX is assigned.
NOTE: If you press No, the the NIC you selected in Device Manager and the ghosted NIC have the same IP address. Since the driver is disabled, this doesn't cause any problems.
This is generally caused because you moved the NIC to a different PCI slot, and didn't uninstall it before shutting down.
To fix the problem:
1. Open a CMD prompt and type:
2. On the View menu, press Show Hidden Devices.
3. Expand Network Adapters.
4. Right-click the ghosted NIC, and then press Uninstall.
NOTE: If Device Manager shows the installed NIC as a #2, you may wish to uninstall and re-install it, for cosmetic reasons only.