I finally solved the problem by following the instructions in Microsoft Knowledge Base Article 249321, "Unable to Log on if the Boot Partition Drive Letter Has Changed" at
http://support.microsoft.com/?kbid=249321 The solution required that I establish a network connection and edit the registry over the network, then swap the drive letter assignments to my C: and D: drives in the registry, according to Microsoft Knowledge Base Article 223188, "How To Restore the System/Boot Drive Letter in Windows" at
http://support.microsoft.com/?kbid=223188