Could be the sleep settings, it could be a loose connection to the display, bad driver, display going bad. A lot of variables there.
Start with updating the drivers for the display and see if that helps. Next try the sleep settings...
1. Go into "Control Panel" and click the "Power Options".
2. Next to the plan that is currently selected click "Change Plan Settings".
3. Now click "Change Advanced Power Settings".
4. Open the "Sleep Setting".
5. Change the settings to what you want and then click "Apply" and then "OK".
If not, most of the other things will require a tech look at it.