Please check if the screensaver is active or not and the time settings.
• Open Screen Saver Settings by clicking the Start button clicking Control Panel, clicking Appearance and Personalization, clicking Personalization, and then clicking Screen Saver.
• Under Screen saver, in the drop-down list, click the screen saver you want to use. Now click on the time and set time as per the time you want it to get activated
Check for the power options settings and also check if some hardware like a wireless mouse or some background program that is running is not letting your systems screensaver getting activated. .
Here’s to Good Karma