Your Windows PC or Laptop does not sleep nor hiberbate automatically no matter how you already set in the Power Management Scheme and Screen Saver.
Solutions:
There are several reasons for the sleep mode not working, you may refer to this article for testing and solution.
But there is another unexpected reason for this: You may have mistakenly disabled the installed utility for power configuration, for example the QuickSet of Dell. In such case, you have to enable it during windows startup.
How to do:
1. Press the Windows Icon, and type MSCONFIG in the search bar to start the System Configuration
2. On the Startup tab, check the QuickSet box (or another similar utility if you PC/Laptop is not Dell), then click Apply, restart your computer.
