A. A. Windows NT 5.0 has changed the boot loader and so trying to install Windows NT 4.0 afterwards Setup may continuously restart each time the computer is started without ever finishing.

Service Pack 4 provides an updated winnt32.exe that allows Windows NT 4.0 to be installed after NT 5.0 so you will need to perform the following:

  1. Copy I386 directory structure from the Windows NT installation CD-ROM
  2. Rename the winnt32.exe to winnt32.old
  3. Copy the winnt32.exe from the service pack 4 CD from the Support\Winnt32\i386to your I386 directory structure
  4. Run winnt32.exe from your local stored copy