How do I stop my computer from automatically shutting off after I don't do anything with it for a while?

Even if I put it in standby it will still shut off. I would say after about 10 or so minutes of not doing anything on it. it will go into a short standby (like 1 minute) then shut off. How can I stop it from doing this? I would like to leave my computer on but I can't because it automatically shuts off after ten minutes. It doesn't even just show the screen savers or nothing just shuts off.