After completing a P2V migration of a server, I was having a problem bringing the server into the cluster using the NLB manager. I traced it down by manually adding the cluster IP address to the new virtual NIC, and receiving an error message stating cluster IP was already assigned to an HP network adapter. Since this was running as a Virtual Machine, there clearly was not a HP NIC installed, and it did not appear in device manager. I found http://support.microsoft.com/kb/315539, which describes a procedure for showing hidden devices. After doing this, the HP NIC appeared and I was able to remove it.