I'm not sure what started it, but one day I fired up my trusty old Windows 2000 Professional box and instead of hopping on the Internet after it's usual 4 minute boot, I got the following error:

“Mobile Devices Properties, The TCP/IP Network Transport is not installed.” 

Surprisingly, I didn't find many Internet sources that could help.  The best one was at TechExams.net (http://www.techexams.net/forums/viewtopic.php?p=17654), as it seemed to have many of the same issues...Windows 2000 Pro, High speed connection via DSL/LAN, McAfee VirusScan, and synchronization with a Windows CE Palm-Size device. 

After many attempts, here's the sequence that (I think) fixed it:

• In Control Panel>Network and Dial-Up connections, open the 'Local Area Connection' Properties dialog and uninstall all of it's components (including TCP/IP), but don't reboot. 
• In Control Panel>Add/Remove Hardware, remove/uninstall the network card
• Now, reboot.
• When it comes back up, reinstall the drivers for the network card (Windows recognized the NIC as 'new' hardare and asked for the drivers.
• Go back into the 'Local Area Network' properties and install the TCP/IP protocol. 
• Reboot and cross your fingers