Question Horizontal black Lines and random flickering on my laptop screen ?

Apr 19, 2022
So before explaining the above mentioned, I want to say something of great importance.
  1. My laptop screen was a generic 60 hz screen, so I wanted to experiment and tried to overclock my monitor(The software I used was Custom Resolution Utility). I overclocked it to 70 hz and it started flickering like crazy, I couldn't see the revert button and accidently clicked save changes. So 5 or 10 mins of flickering, till I remembered that I have a TV and plugged the HDMI and reverted the changes back to 60 hz, however the damage was done.
  2. I went to Tech Shop and got a new 120hz display, the tech guy told me that there was nothing wrong with my old 60hz display and he tested it. Anyway at first there was no noticable problems, after a while every time i moved my screen there was flickering.
  3. Went to the same tech shop, got the LCD cable for the display changed with a new one, no more flickering when I move my laptop screen, no problems. However from time to time random black horizontal lines appear on my screen.
In your opinion what could be causing it ? I'll be very thankful, if someone could help !