VBA code to detect windows user id

Here's the code:

Public Function GetLDAPUserName() As String

Dim SI, colItems As Variant

Dim pos As Integer

On Error GoTo tryalternate

Set SI = CreateObject("ADSystemInfo")

pos = InStr(SI.UserName, ",")

GetLDAPUserName = Mid(SI.UserName, 4, pos - 4)

On Error GoTo 0

Exit Function

tryalternate:

Set SI = GetObject("winmgmts:\\.\root\cimv2")

Set colItems = SI.ExecQuery("Select * From Win32_ComputerSystem")

For Each objItem In colItems

GetLDAPUserName = objItem.UserName

Next

On Error GoTo 0

End Function