DELL Inspiron 5100 screen white lines

I have a Dell Inspiron 41113/sdpp/2015-5100 MFG yr 2016  laptop. 16 gb ram, new 500gb ssd. the screen has recently started blinking white vertical and horizontal lines on boot up and during use. I ran the lcd test , came back no issues, ran dell support assist check on all hardware and no issues. all drivers are current. the screen is not always blinking white, it appears to occur about 30 seconds after boot then stops..clear hd screen on logon into windows 10 then about 15 second later white screen again and it continues. to me it appears to happen maybe when a process or function is activated in the background. during whitescreen, If I open a folder or explorer the screen goes clear again, then say choosing an file , goes back to whitescreen. I was told the cable on the laptops can fray near the hinges but that doesnt seem to be the issue here. I did reinstall windows 10 recently but again, all the drivers and programs went back in with no problems ?? any suggestions?? thank you