n a scenario where you have physically removed hardware from a machine you can no longer see it in device manager.  This does not mean that it is gone.  Evidence of that is, if for example you had a network card that had a Static IP address set and you remove the card and add a new one then try to set the IP address to the same as the old NIC you will get an error message. The error might look something like “The IP address 192.168.30.100 you have entered for this network adapter is already assigned to another adapter (Microsoft Virtual machine Bus Network Adapter #3) which is no longer present in the computer.  If the same address is assigned to both adapters and they both become active, only one of them will use this address.  This may result in incorrect system configuration”.  In Windows Server 2008 R2 and Windows 7 it actually gives you an opportunity to “remove the static IP configuration for the absent adapter”. If you say Yes, this will eliminate the IP conflict problem but does not solve the problem of the adapter still being present in the machine.  In older versions of the OS, it was even worse because every time you go into network properties it gives you an error message.  Another way this comes up is if you move a virtual machine from one host to another.  Like in the case of moving from Virtual Server 2005 R2 to Hyper-V or perhaps you are moving from one Hyper-V machine to another but you did not do an export, you just moved the VHD’s and created a new machine. 

Getting rid of these old devices is actually very simple.  Well, it is simple if you know how ;)

Before you proceed, I recommend that you confirm that you have a good backup.  I have never had a problem with this but hey, it is your server not mine.