Mad Cow AKA Bovine Spongiform Encephalopathy (BSE) and Creutzfeldt-Jakob Disease (CJD)
It sounds like Fast Logon Optimization could be a culprit but if W2K machines are affected then it is likely some other network issue. My guess is users are logging on with cached creds sometimes. I would examine the network closely as well as the network settings on the clients. You may have to optimize protocols and provider order. You may not have AD setup correctly for site awareness. You did not say how your network is laid out. Do you have DCs that are not well connected or all they all on one LAN subnet?
You can type SET at a CMD prompt to see what LOGONSERVER is.
_________________________
Give a man a fish and he will be back for more. Slap him with a fish and he will go away forever.
