Ghost or hidden Network Card

When you trying to set the IP address on a network adapter, you may receive the following error message:

"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? "

 

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Solution:

Download devcon.exe (http://support.microsoft.com/kb/311272) 

From a command prompt ("run as administrator" if you are on Vista or  above)

devcon findall = net 

or 

devcon listclass net 

 

Note: In the output of the previous commands, there is a line for the ghosted network adapter that is similar to the following:

PCI\VEN_10B7&DEV_9200&SUBSYS_00D81028&REV_78\4&19FD8D60&0&58F0: 3Com 3C920 Integrated Fast Ethernet Controller (3C905C-TX Compatible) 

 

Remove the ghosted device by typing the following syntax:

 

devcon -r remove "@PCI\VEN_10B7&DEV_9200&SUBSYS_00D81028&REV_78\4&19FD8D60&0&58F0" 

 

 

Source: http://support.microsoft.com/kb/269155