If you use Remote Desktop to install a Windows XP service pack, and you are disconnected during the install, you may not be able to reconnect.
A Windows XP service pack installs a new copy of Winlogon.exe, but the required mating libraries (DLLs) are NOT installed until the computer restarts. The resulting mismatch prevents you from logging onto the Remote Desktop.
If you experience this problem, you will have to logon to the remote computer locally, respond OK to any error messages, and press Finish when prompted.
To avoid this problem, DO NOT use Remote Desktop to install a service pack. Use the network installation package, XPSPn.exe to run:
XPSPn.exe /f /q
to quietly install the service pack.
NOTE: n is the service pack number.
NOTE: See tip 1981 for additional switches.