I suspect that GameGuru has missed something.
GameGuru, in the power options of your control panel, take a very careful look again your power options. Look through all the tab settings again. There is an option where it says something like "computer goes into standby after" so many minutes and it gives you a drop down menu box for the duration. I take it you are using a PC rather than a laptop, DO NOT use stand-by or Hiberation mode for a PC - they are desgined for use by a laptop only.