If it is out of DNS, then it could still be in WINS.
Open WINS manager, expand the server, then on Active Registrations right-click and choose Find By Owner.
Then, select All Owners and click OK.
Let the list come up.
Then, sort the display byRecord Name, and check for NOC1. If you see it, right click every entry (you might have several for different NetBIOS codes like 03h, 00h, 20h, etc)and choose Delete.
In the warning box that comes up, choose "Replicate deletion of the record to other servers (Tombstone). Click OK.
Keep doing that until NOC1 is entirely gone.
This will force the records to be tombstoned immediately, thereby deleting them.
That should take care of it.
hope this helps