Declare Function GetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, nSize As Long) As Long

Sub Get_User_Name()

                ' Dimension variables
                Dim lpBuff As String * 25
                Dim ret As Long, UserName As String

                ' Get the user name minus any trailing spaces found in the name.
                ret = GetUserName(lpBuff, 25)
                UserName = Left(lpBuff, InStr(lpBuff, Chr(0)) - 1)

                ' Display the User Name
                MsgBox UserName
End Sub