I just upgraded my Mac at work from 10.2.8 to 10.3.3. Since doing so, the SMB network is not working properly. This is the only mac here, the other 10 or so computers are WIN2K. The mac seems to start okay and be able to see all network drives on the pcs, but after a few minutes it displays a dialog stating that the drive that is mounted is no longer available and gives me the option to try to re-establish or to disconnect. no matter what I do, if I check the network again (click on go->network->) I see what seems to be an arbitrarily slimmed down list of network drives (if I see any at all). What I mean is that the remaining list can change each time, as in no specific drive is the problem. Is this something I can fix? Like I said, it just started with the addition of 10.3.3 from 10.2.8. It worked fine before.
HELP, please...

brian