Here's a VBS script that works for me. Good luck.
dim OlyNet
dim OlyPrinter
dim OlyFSO
dim OlyShell
dim OlyDrives
dim i
dim cmd
on error resume next
set OlyNet = WScript.CreateObject("WScript.Network"

set OlyPrinters = WScript.CreateObject("WScript.Shell"

Set OlyFSO = WScript.CreateObject("Scripting.FileSystemObject"

set OlyShell = CreateObject("WScript.Shell"

set OlyDrives = OlyNet.EnumNetworkDrives
'----- Set Drive Mappings (This clears any existing mappings)
DriveMapping "G:", ""
DriveMapping "H:", ""
DriveMapping "I:", ""
DriveMapping "J:", ""
DriveMapping "K:", ""
DriveMapping "L:", ""
DriveMapping "M:", ""
DriveMapping "N:", ""
DriveMapping "O:", ""
DriveMapping "P:", ""
DriveMapping "Q:", ""
DriveMapping "R:", ""
DriveMapping "S:", ""
DriveMapping "T:", ""
DriveMapping "U:", ""
DriveMapping "V:", ""
DriveMapping "W:", ""
DriveMapping "X:", ""
DriveMapping "Y:", ""
DriveMapping "Z:", ""
DriveMapping "G:", "\\servername\share"
Sub DriveMapping(Drive, Share)
For i = 0 to OlyDrives.Count -1 Step 2
if LCase(Drive) = LCase(OlyDrives.Item(i)) then
if not LCase(Share) = LCase(OlyDrives.Item(i+1)) then
OlyNet.RemoveNetworkDrive Drive, true, true
Else
Exit Sub
End if
End if
Next
OlyNet.MapNetworkDrive Drive, Share
End Sub