should happen that, after removing a virtual nic on a vm running windows 2008R2, and after re-adding a newone, you cannot connect using RDP protocol.
The problem is related to RDP-Tcp connection. If you execute Remote Desktop Session Host Configuration unnder connection you can find the default connection named RDP-Tcp
If you have a look deeper right clicking on the connection and selecting properties and then navigating into Network Adapter tab
you can see that normally, as network adapters, is selected the option All network adapter configured with this protocol, but if you fist remove an adapter so that the vm temporaly remains without, and after you ad a newone you can get an error looking at that tab.
So the only way to solve the problem is to delete the actual connection and create a new using the wizard Create New Connection located on the right frame.