In tip 2766, I described how to manually prevent Windows 2000 Explorer from opening a new window when you map a network drive.
To permanently prevent this behavior:
2. Copy / Paste the following to a NoWindowMappedDrive.reg file:
3. Merge the NoWindowMappedDrive.reg file with your registry or run regedit /s NoWindowMappedDrive.reg.
4. Log off and Log on for this setting to take effect.