Так чтоль ?
Код:

#include <WinAPI.au3>
$DiRT = "DiRT.exe" ; Если запущена игра DIRT - то отрубаем её.
While 1
If _IsFullScreen() = 1 Then
Sleep(3000)
If ProcessExists($DiRT) Then ProcessClose($DiRT)
EndIf
WEnd
Func _IsFullScreen()
Local $hWnd = DllCall('user32.dll', 'hwnd', 'GetForegroundWindow')
$hWnd = $hWnd[0]
If (@error) Or ($hWnd = 0) Then
Return SetError(1, 0, -1)
EndIf
If (StringInStr(WinGetClassList($hWnd), 'SHELLDLL_DefView') = 0) And (BitAND(WinGetState($hWnd), 2) = 2) And (_WinAPI_GetClientWidth($hWnd) = @DesktopWidth) And (_WinAPI_GetClientHeight($hWnd) = @DesktopHeight) Then
Return 1
EndIf
Return 0
EndFunc