ME & Win2K Pro Browsing Problems

I have a network installed that consists of 3 Win2K servers. The domain controller has DNS, WINS, and has the registery key set for IsDomainBrowser “True”. A workstation running ME, and 1 running Win2K Pro are unable to browse the network intermittantly. They are both pointed at the DC for the DNS as well as WINS. If they (the 2 workstations) are shut down and brought back up, they are again able to browse the network. Mapped drives continues to work without fail.