I've also got a WG311v2 PCI wireless client in a Win2K box; periodically, it drops the network connection (ipconfig says the media is disconnected and /renew won't repair the connection). The actual period ranges from minutes to days, and *seems* to start out longer after resetting the PC, but I don't have any hard statistics on this behavior yet. I'm running with WPA-PSK, and haven't tried running with encryption disabled or with WEP to see if there's any connection (this would be weird, but possible).
I can repair the connection by simply opening the Smart Configuration system tray utility and doing anything that causes it to "validate settings", e.g., disabling/enabling encryption, changing the SSID selection from netgear to ANY, changing the profile (I have two that are exactly the same). Presumably, there's some sort action performed by the utility (card reset?) that causes the problem to disappear.
It's more annoying than anything else, since I don't have to reboot the system to fix it, but I was wondering if anyone else has see this on Win2K (it's not XP, so the zero configuration isn't running). I've already updated the drivers to the latest version to get WPA-PSK support.