Forces Windows to keep the display on (temporarily disables sleep mode while running). Netflix's silverlight app failed to do this for me :/

screenon.py

import os
import sys

import ctypes

ES_AWAYMODE_REQUIRED = 0x00000040
ES_CONTINUOUS = 0x80000000 
ES_DISPLAY_REQUIRED = 0x2 #Forces the display to be on by resetting the display idle timer.
ES_SYSTEM_REQUIRED = 0x1 #Forces the system to be in the working state by resetting the system idle timer.

def not_null(result, func, arguments):
    if result == 0:
        raise WinError()

SetThreadExecutionState = ctypes.windll.kernel32.SetThreadExecutionState
SetThreadExecutionState.restype = int
SetThreadExecutionState.argtypes = (ctypes.c_uint, )
SetThreadExecutionState.errcheck = not_null

def main(argv):
    sys.stdout.write("Keeping display on. Press enter to exit.\n")
    SetThreadExecutionState(ES_CONTINUOUS | ES_DISPLAY_REQUIRED)
    sys.stdin.read(1)
    
if __name__ == '__main__':
    sys.exit(main(sys.argv) or 0)

FWIW, I use this now: https://github.com/joba-1/Present

It is sourcecode for a self contained exe with only a few kb size. No python, no shell, no install :)

You need platformio though, to build it yourself -> no viruses, no calling home, no trust needed - just look at it :)