Recently my computer, a desktop running Windows 10, stopped going into Sleep mode.

I have tried all the recommended things:
1) Restore the power usage plan to defaults
2) Set the Multimedia Settings to "Allow sleep"
3) Set Hybrid Sleep setting to "Off"
4) Set put the computer to sleep at "1 hour"
5) Set Turn off hard disk after... setting to "20 minutes"
6) Set Turn off the display setting to "15 minutes"
7) Powered down all peripherals

The display does indeed turn off after 15 minutes of inactivity. The Sleep mode never comes. It used to Sleep, as recently as a week or 10 days ago, no changes have been made to hardware or software unless a Windows update came in the middle of the night when the computer was supposed to be sleeping.

Have I missed something?

tanstaafl.