I would like NT (4.0SP4, if it matters), to attach a drive on system startup, rather than having to be logged in...
[...]
Is this possible?
And a ridiculously easy answer... :-)
Sure. You need the AUTOEXNT tool from the Windows NT resource kit. Or, if you prefer...
http://www.ntfaq.com/ntfaq/download/autoexnt.zip
Be careful about which user account under which you arrange for the drive to be mapped. The local "System" account on an NT machine has no privilege in a network context (even though it is all-powerful in a local context), and people often make the mistake of trying to use it.
Keith