Hi,
Does the monitor turn off when it's idle or does it turns off by itself even you're doing something with it?
- Start by changing some settings in Power Option.
- In Power Options click on Change plan settings on the select power plan.
- Set Turn off the Display to Never and do the same with Put the computer to sleep then click Save changes.
- Test weather if it will still go to sleep automatically or not.
- If it will still continue to sleep even if you're doing something with it you can still downgrade back to Windows 7.
- Click Start then go to Settings, click on Update & Security and on the left pane click Recovery then you'll see Go back to Windows 7.