Prevents the system from entering sleep or turning off the display while the current application is running
#include <WinAPIProc.au3>
_WinAPI_SetThreadExecutionState ( $iFlags )
| $iFlags | The thread's execution requirements. This parameter can be one or more of the following values. $ES_AWAYMODE_REQUIRED $ES_CONTINUOUS $ES_DISPLAY_REQUIRED $ES_SYSTEM_REQUIRED $ES_USER_PRESENT  | 
| Success: | The value is the previous thread execution state. | 
| Failure: | 0. | 
The _WinAPI_SetThreadExecutionState() function cannot be used to prevent the user from putting the computer to sleep.
Applications should respect that the user expects a certain behavior when they close the lid on their laptop or press the power button.
This function does not stop the screen saver from executing.
According to Microsoft Docs $ES_USER_PRESENT should not be used, and $ES_AWAYMODE_REQUIRED should be used only when absolutely necessary.
Constants are defined in APIProcConstants.au3
Search SetThreadExecutionState in MSDN Library.
#include <MsgBoxConstants.au3>
#include <WinAPIProc.au3>
_Example()
Func _Example()
    ; disable ScreenSaver and other windows sleep features
    _WinAPI_SetThreadExecutionState(BitOR($ES_DISPLAY_REQUIRED, $ES_CONTINUOUS, $ES_SYSTEM_REQUIRED, $ES_AWAYMODE_REQUIRED))
    MsgBox($MB_OK, 'Testing', 'Close this tester window when you be sure that your ScreeSaver not runing.')
    ; back to normal windows behavior
    _WinAPI_SetThreadExecutionState($ES_CONTINUOUS)
EndFunc   ;==>_Example