Blurred Solarised Display on DELL all-in-one PC

Hi all. My PC "Inspiron 24 3459" intermittently switches between a clear display and blurred or solarised display: Below is a picture of a solarised display (d). The solarised effects are sometimes apparent on start-up and in BIOS. Dell Support assistant couldn't identify any problem, re-installed display drivers and unchecked Windows Error Reporting Systems all proved abortive. No apparent screen damage...what could be the cause and how do I fix this (d).

 

Have you tried bumping the side of your all-in-one to see if it changes? Could be an internal loose connection.