CVS for Windows NT 4 sp6+
Reason for this post:

The manuals/faq on site are sketchy and do not solve the problem.
It takes time and patience and sometimes tearing hair!

Objective: Install it in a non C drive like d: etc.
Login as Administrator.
Download from http://www.cvsnt.org/ and run the installation
The control panel applet comes up easily - look in control panel to run it.
create an empty .passwd file in the location of env var HOME (find by doing set HOME from cmd prompt).
Create a repository in the drive where you installed your cvs app(should work for other drives too, haven't tested. Apply, then stop (if req.), and start the server.
Create a passwd file in the CVSROOT directory under your repository.
It should contain an entry like:

Administrator:

BTW: I am not in a domain so :ntserver: doesn't work!
I used cvshome=x:\cvs\java

cvs passwd

was used to change password.

IMPORTANT: You must have a CVS repository set in C: drive, say c:\cvs. You may end up not using it but that is fine. This is the key to the problem.

Then I set cvshome:

CVSROOT=:pserver:Administrator@taragana:x:\cvs\java

I am feeling very very tired. If you want more details write to me.