I know exactly what you are speaking of i had the same issue after trying every possible software fix i diagnosed the issue to be a lose connector of the back of the screen. Screen blinks intermittently at random horizontal flicking lines from time to time well lucky its a rather simple fix watch the YouTube video i linked for a screen replacement on the y50 but instead of replacing the screen just remove and snugly reattach the display connector and tada problem solved at first i was hesitant about doing this myself but once i was able to stomach it was not that hard https://www.youtube.com/watch?v=7BqVuCKe...