i have a problem my cousin is coming over and i have to leave it my computer with him i don't want to give it to him because he always ends up messing it up, i dnt want to put a password on it cause it wud seem rude i just don't want him to use it. is there someway i can prevent the computer from starting by deleting some file and then easily restoring it myself so it actually seems to him as if the computer is not working