con la api 
EnumDisplayDevices se puede obtener la marca del monitor.    
Código vb:
Ver original- Const CCDEVICENAME As Short = 32 
-   
-     Private Structure DISPLAY_DEVICE 
-         Dim cb As Integer 
-         <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=CCDEVICENAME)> _ 
-         Dim DeviceName As String 
-         <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)> _ 
-         Dim DeviceString As String 
-         Dim StateFlags As Short 
-         <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)> _ 
-         Dim DeviceID As String 
-         <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=128)> _ 
-         Dim DeviceKey As String 
-     End Structure 
-   
-     <DllImport("user32.dll")> _ 
-     Private Shared Function EnumDisplayDevices(ByVal Unused As Integer, ByVal iDevNum As Short, ByRef lpDisplayDevice As DISPLAY_DEVICE, ByVal dwFlags As Integer) As Integer 
-     End Function 
es la que tiene el nombre del monitor y marca. 
saludos.