Is there any way to disable the computer from booting itself up?

I've been having an issue where the computer will reboot itself about a minute or so after I attempt to shut down, it doesn't happen every night but rather a couple of times a week. Perhaps there is a way to deny it from booting on a schedule like 10 PM to 7 AM or deny any Scheduled tasks from starting itself to perform them (I've checked and changed any scheduled tasks to just perform at start up)