We are having an increasing number of computers have troubles when first trying to login after a restart. After the restart, when you hit Control-Alt-Delete to login, you are sometimes logging in to workstation only and not to the server. We have "Enable Workstation Only if not connected" option enabled on the client, but not the "Workstation Only" - so the users cant see the checkbox. If you cancel out of the login 1-2 times, you will then be able to login to the network and everything is fine. It seems like the computer isnt pulling an address fast enough before the client starts.

I checked the event logs on the problem computers and all of them have this one in common, right around the time of trying to login:

Event Type: Warning
Event Source: Dhcp
Event Category: None
Event ID: 1003
Date: 8/18/2008
Time: 10:17:19 AM
User: N/A
Computer: <computer name>
Your computer was not able to renew its address from the network (from the DHCP Server) for the Network Card with network address 001B211ED10D. The following error occurred:
The operation was canceled by the user. . Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.
Ive searched around and tried a few things but nothing seems to help. I tested a client with all the current patches and current NIC drivers, but that doesnt seem to help either. We are running NW 6.5 SP7. Any help would be greatly appreciated!!!