How about this:
#RequireAdmin
Local $RunDLLexe = 'rundll32.exe'
Local $Parameters = @WindowsDir & '\system32\shell32.dll,Control_RunDLL ' & _
@WindowsDir & '\system32\desk.cpl desk,@Themes /Action:OpenTheme /file:"' & _
@WindowsDir & '\Resources\Ease of Access Themes\hc1.theme"'
ShellExecuteWait($RunDLLexe, $Parameters, @SystemDir)
Local $winClass = "[CLASS:CabinetWClass]"
WinWait($winClass, '', 5)
If NOT @error then WinClose($winClass)