Converting Microsoft Windows NT / 2000 Workstation to Server

Note: Within Windows NT 4 and Windows 2000 the below given registry keys are secured by two system threads. Therefore you'll need to change registry values from outside of the system. Use a different OS or remote registry function.

Windows 2000 Professional to Windows 2000 Server
See NT 4 Workstation to NT 4 Server

Windows 2000 Home Edition to Windows 2000 Professional
Modify SETUPREG.HIV found on installation CD. Allows the following features:
Dual-CPU
Dynamic Disks
Desktop Sharing

Windows 2000 Trial Version (Time Limit Removal)
Locate \i386\setupreg.hiv on your Windows CD.
Copy the file to your desktop and remove ReadOnly attribute.
Run REGEDT32.exe and click on either HKEY_LOCAL_MACHINE or HKEY_USERS (only place to load a hive).
In the menu click Registry and Load Hive. Browse to your desktop for setupreg.hiv and select it.
You'll be asked for the import path. Just name it TEMP (doesn't matter).
You should see a new folder named TEMP where the hive is imported. Move to \ControlSet001\Services\setupdd
Find the key named <No Name>. You will see a value of zeros and letters (00A30200000000000800000002000000).
To remove the trial time limit change A302 (120 days) to 0000.
In the menu click Registry and Unload Hive. It will give a warning which can be ansered YES.
Now substitue the original file with the edited setupreg.hiv (you might want to burn a new CD copy...).
During installation it will indicate on the screen that this is a trial version, but now it isn't anymore.

Windows NT 4 Workstation to Windows NT 4 Server
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\ProductOptions\
HKEY_LOCAL_MACHINE\System\Setup\SystemPrefix
ProductType Value OS version SystemPrefix bit
WinNT NT Workstation OFF = 0
ServerNT NT Server ON = 1
LanmanNT NT Server (Enterprise Edition) ON = 1

011B0000 004038E4 -> 004038E4 = 0000 0000 0100 0000 0011 1000 1110 0100
C50B0000 00603C30 -> 00603C30 = 0000 0000 0110 0000 0011 1100 0011 0000

Windows NT 3.51 Workstation to Windows NT 3.51 Server
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\ProductOptions\
ProductType Value OS version
WinNT NT Workstation
ServerNT NT Server
LanmanNT NT Server (Enterprise Edition)