Use the DwmIsCompositionEnabled function to determine whether Aero is enabled.

private static extern int DwmIsCompositionEnabled(out bool enabled);

Private Shared Function DwmIsCompositionEnabled(ByRef enabled As Boolean) As Integer

     DwmIsCompositionEnabled(Enabled)

     DwmIsCompositionEnabled(AeroEnabled)

Use the DwmIsCompositionEnabled function to set the value of non-client rendering attributes for a window.