live os
boot from another os, load system hive
<system>\CurrentControlSet\Control\Session Manager\Executive
has 3 32-bit numbers, zero out the one in the middle
<system>\Setup\systemprefix
zero out 3 bytes starting with the second byte (0-based indexing)
so from the 0x30


installmedia
modify the setupreg.hiv (which is loaded as HKLM\System during textmode setup) in your Win2K RC2 Alpha installation source so that you have 16 zeroed out bytes as the default value under ControlSet001\services\setupdd