My Network Places relies on WINS for computer population.
Try checking your domain for Master Browser Wars - there are a few utilities to do this: Browmon and Browstat (in the resource kit and support tools). Keep refreshing the data and see if your masters are changing. If they are, you will need to suppress this from happening. On servers that do not need to be the master, change the following reg. key:
\\HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\Browser\\Parameters\\ISMasterBrowser
To "Auto" (no quotes!) and restart the computer browser service on that machine. Do this for everything that is competing for the master and you will eventually have the entire list again.
~Intruder~
CEH, CISSP, MCSA/MCSE 2000/2003