Screen display blackout - must manually power off

[mydeltas]

Hi,

There is screen blackout issue for following situations:

System is idle for 1 hour

I locked the screen for 30 minutes ,when i try to unlock - screen not display anything
laptop is working , so all black not able to login etc.

- open chrome://extension and click on get more extendsions .. message page load then blackout..

-- some of few video / picture viewing in full screen mode -screen goes black

in all above situation i have to power off manually and then have to restart system..

its too irritating  first time i have experienced this kind of issue with any OS

Regards,