Windows 2000 system event log shows errors after startup:

Event : 2506
Source : Server
The value named IRPStackSize in the server's Registry key LanmanServer \ Parameters was invalid. The value was ignored, and processing continued.

This is caused by the IRPStackSize value having been set to less than 0x11 which is the legal minimum value. Unfortunately Symantec's NAV2000 and perhaps other packages reset this value below the legal minimum. You can ignore the message but this is not recommended. There are reports that sporadic network errors were eliminated after IRPStackSize was returned to its default. To fix, apply the following Windows 2000 registry hack:

Hive: HKEY_LOCAL_MACHINE
Key: SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
Name: IRPStackSize
Type: REG_DWORD
Value: 0x11