Server requires re-activation every few hours.

Giganews Newsgroups
Subject: Server requires re-activation every few hours.
Posted by:  mu (…
Date: Thu, 16 Mar 2006

I have a Windows 2003 server, (with all updates, to date) that "locks up".
You are unable to logon remotely and logging on locally fails until you
activate the server (on line, so far). Of course, it was activated and ran
for about 1 year. The failure did not coordinate with an update (that we know
of anyway) and no other HW or SW changes have been made.
We may have had two servers that behaved this way but one has been rebuilt
and no problems from it, since rebuild. Not enough info remains to be sure
they were the same.

What can cause a demand for reactivation?  (Note: No hardware or software
changes have been made.)