DELL HELP PLEASE, HORIZONTAL LINES ON SCREEN WHILE GAMING

My laptop model is dell inspiron 15 7559 i7 4k touchscreen, i am facing a screen issue on my dell 4k UHD touch display, when i play any game the screen starts to show these horizontal lines (video link at the bottom) 

i have tried following solutions with NO success:
-updated nvidia and intel drivers
-Changed PC resolution
-Changed game refresh rate, V-sync, resolution
-turned On/Off v-sync & tripple buffering from nvidia Control panel
-tried to play game in window mode doesnt help too

Now following details may help u understand the issue:
-when i start game from intel gpu it doesnt show lines in game
-when i connect external monitor with hdmi and play game with nvida or intel it doesnt show these lines
-The lines only show during gaming with nvida not while browsing watching movies etc.. but dont show up on external monitor even with nvida

My display is 4k UHD touch screen, laptop is in warranty i dont want to send it back for repairs unless necessary.. any help would be appreciated Sir, hope for a good response THANKS..
VIDEO LINK: LINK: www.dropbox.com/.../4k gaming flicker.avi