I am using Inspiron 15 3000 series laptop. It started behaving strange. The laptop screen turns off itself, although I am using laptop actively.  The screen will not wake up unless I press power button twice, first to make laptop go to sleep and then wake it up with second press.I tried to change Power and Sleep settings by choosing Never to sleep. I tried creating a new power plan but it did not help either. I customized multiple options from Dell Power Manager Lite, but nothing is working.Please help on this to resolve this issue.