Windows 7: Windows 7 intermittent connection problem to windows 2000 share

I've got a network with a 2003 DC and two windows 2000 servers. 35 clients, mixed between windows xp and 7-64bit.

For the past 48 hours or so the 7 machines randomly lose connection to one of the 2000 servers. This is a transient condition; it corrects itself after a period of time ranging from a few seconds to a few minutes. During this time, the 7 machines are unable to see any of the network shares, the website that is hosted on the machine, and are unable to ping it either by dns address or direct ip address. For all intents and purposes the machine appears to be off or disconnected from the network for the 7 machines. This may not occur for hours, and then may happen several times in an hour. It appears totally random.

While this is happening, the xp machines can see the server just fine. The 7 machines can see everything else, including the other 2000 server. I've examined the logs on some of the 7 machines, the affected 2000 server, and the 2003 DC, and I can't find anything out of place.

There have been no updates applied to any of the machines. I have swapped the cabling on the "disappearing" server all the way back to the switch, and the switches appear to be okay as well.



I've tried rebooting all affected machines, as well as the DC and the affected server.

Frankly, I'm baffled. Any help would be greatly appreciated.