Public Function GetUserName() As String
Dim NameSpace As String
 
    On Error GoTo noUser
    NameSpace = "root\cimv2"    'c'est le namespace par défaut
    Set p_objSWbemServices = GetObject("winmgmts:{impersonationLevel=impersonate}!\\.\" & NameSpace)
     
    Set p_objSWbemObjectSet = p_objSWbemServices.ExecQuery("Select userName from Win32_ComputerSystem", , 48)
 
    For Each p_objSWbemObject In p_objSWbemObjectSet
        GetUserName = p_objSWbemObject.userName
        Exit Function
    Next
    Exit Function
noUser:
    GetUserName = ""
End Function

msgbox Environ("USERNAME" )

Private Declare Function GetEnvironmentVariable Lib "kernel32" Alias "GetEnvironmentVariableA" (ByVal lpName As String, ByVal lpBuffer As String, ByVal nSize As Long) As Long
 
Public Function GetEnvVar(ByVal VarName As String) As String
    Dim sVar As String, lVar As Long
    lVar = 50 '(ceci représente le nombre max de charactères à récupérer...)
    sVar = String(lVar, 0)
    lVar = GetEnvironmentVariable(VarName, sVar, lVar)
    GetEnvVar = Left(sVar, lVar)
End Function
 
Private Sub Form_Load()
   msgbox GetEnvVar("USERNAME" )
End Sub