Last night I installed the 8 latest updates for Windows 2000 on my unit:

Security Update for Windows 2000 (KB896423)
Security Update for Windows 2000 (KB899588)
Windows Malicious Software Removal Tool - August 2005 (KB890830)
Cumulative Security Update for Internet Explorer 6 Service Pack 1 (KB896727)
Security Update for Windows 2000 (KB893756)
Security Update for Windows 2000 (KB899587)
Update Rollup 1 for Windows 2000 Service Pack 4 (KB891861)
Security Update for Windows 2000 (KB901214)

The unit shut down and re-booted normally, but when I attempted to log into
the system, it comes back to the CTRL+ALT+DEL screen pre-login (which was set
to NOT show for users logging into the system originally.)

No matter what user account for the domain (domain admin, admin, user, power
user, guest, etc) or on the local box (admin only, no local user accounts,
but they were attempted anyway) all return to the same login screen again.  
Safe mode returns the same results for logging in as administrator on the
local box.

A parallel install of W2K that was already residing on the box for testing
purposes almost a year ago but never updated, logs in fine locally.  This is
therefore not hardware related and isolated to the active W2K install and a
result of the latest windows update (and the insistant install/"update" of
the windows update software.)

Any help with how to correct this without re-imaging the system will be
greatly appreciated, and I have halted the updating of any other units in the
domain until this is resolved (this was the first unit on the domain updated.)

Todd