I think you will find, your computer is not turning off, but going into sleep or hibernation mode.
But to get a more specific answer, we need to know what operating system you are using, and an overview of your computers specification.
Best Black Friday Deals 2017
How modern book design was influenced by illustrated manuscripts
Best Black Friday Apple Deals 2017
Les meilleurs logiciels de montage vidéo gratuits (en 2017)