A. When moving from a single CPU to dual-CPU, multiprocessor versions of a number of NT files, including the HAL and the OS kernel, must be installed.  The UPTOMP.EXE utility, contained in the NT Resource Kits, installs the multiprocessor files.   The files can be installed manually (see the MS Knowledge Base articles Q156358 "How to Manually Add Support for a Second Processor" and Q168132 "After Applying Service Pack NT Reports Single Processor").

The MS Knowledge Base article Q142660 (http://support.microsoft.com/support/kb/articles/q142/6/60.asp ) "Upgrade from Uni- to Multiprocessor (Uptomp.exe) and Win32k.sys" describes a known problem when using UPTOMP.EXE on a version 4.0 NT system.  The fix, described in the article, adding the following line to the file uptomp.inf, located at the base directory of the Resource Kit installation, e.g., reskit.

win32k.sys=0, 2, win32k.sys

Finally, if you install the multiprocessor files on a system to which a Service Pack has been applied, you probably need to reapply the Service Pack after running UPTOMP.EXE and before rebooting.  Until you reapply the Service Pack your disk contains a mix of file versions, with the multiprocessor files at the revision level of the distribution media and files already present at the Service Pack revision level.  Such a mix of versions can cause your reboot to fail.

For Compaq Proliant servers, Compaq has provided a very automated method of changing the HAL, which does not require the NT Resource Kit, and is distributed on the Compaq SmartStart CD. 45 minutes seems to be the time from opening the case till the last reboot and that was by a user!