Performing a restore under Windows 2000 can make your network adapter disappear. If you perform a full restore or a full System State restore over a clean Windows 2000 installation, the Device Manager may fail to show the network adapter at the end of the restore. Instead, a new device may be reported. Worse, you won't be able to re-install the network adapter.
The reason, according to Microsoft, is that before you can do a restore under these circumstances, Windows 2000 requires that it be reinstalled using the same method used to install the original installation. If you did the original installation using an installation script and try to reinstall using the Windows 2000 CD-ROM, for example, odd things can happen in Device Manager.
Microsoft offers two solutions for the problem. The first is to perform an in-place upgrade of Windows 2000 after you perform the restore operation. If this doesn't work, Microsoft suggests the following work around:
First, make sure you have a secondary protocol, such at NetBEUI, installed. If you don't have one installed by default, install one now. If the computer is a domain controller restart the system in the Directory Services Restore mode. If it isn't a domain controller, restart the computer in "Safe Mode with Networking." Now remove the TCP/IP protocol from the properties list of the local area connection. Now restart the computer again as you did previously -- in Directory Services Restore mode if it is a domain controller
This was first published in January 2004