I have a Windows 2000 Server and a mixed network of clients(Win 98SE, winMe, WinXP – 25 computers)on some of the win98SE clients I log on and can browse network but after a while (maybe an hour or two)when I click on network neighborhood it tells me “cannot browse network” I can log off and log back on and all is well- I can browse again. My network has been running fine for a year! I run local DNS for WinXP and WINS for all others. I can still ping the computers on the network even when I can’t browse.