10-24-2018 09:34 AM
Welcome to the Community Forums.
You can isolate the issue if it is happening only in the built in LCD panel and not when connected on any external display. Check if the same spot and lines appear in the BIOS to differenciate it from GPU / drivers issues.
You can try to apply the pixel policy test as described here. If warranty is still active then perhaps you can avail of the services offered by tech support specially if it does isolate on the LCD panel itself.
I hope this helps answer your query.