USERNAME

Private Function UserName() As String
Const UNLEN = 256   ' Max user name length.
Dim user_name As String
Dim name_len As Long

    user_name = Space$(UNLEN + 1)
    name_len = Len(user_name)
    If GetUserName(user_name, name_len) = 0 Then
        UserName = "unknown"
    Else
        UserName = Left$(user_name, name_len - 1)
    End If
End Function

Private Sub Command1_Click()
MsgBox UserName, , "UserName"
End Sub