A significant number of tips on this site call for an alternate (parallel) install of Windows NT 4.0.
Microsoft has finally written a knowledge base article, Q259003 - How and Why to Perform a Parallel Installation of Windows NT 4.
The article fails to mention the following steps that should be taken before and after the alternate install is completed:
1. At a command prompt, type Attrib -r -s -h c:\boot.ini.
2. Open C:\boot.ini in Notepad.
3. Add Primary to the two boot menu options, to make them easier to identify later ("Windows NT Workstation Version 4.0 (Primary)").
1. Boot either install and use Control Panel / System / Startup/Shutdown to select the primary instance in the Startup box. Set the timeout in Show list for n seconds box.
2. At a command prompt, type Attrib -r -s -h c:\boot.ini.
3. Open C:\boot.ini in Notepad.
4. Rename the parallel install instances to make them easy to identify. You may wish to remove (Primary) from the primary instances.
5. You may wish to rearrange the sequence of the entries, making the two primary instances first. You may also want to delete the VGA Mode entry of the parallel install.
6. If you have a boot floppy, copy c:\boot.ini to it.
7. At a command prompt, type Attrib +r +s +h c:\boot.ini.