This could be a hardware issue with the LCD panel which would require repair. If this is a recertified model you should have received documentation with support contact info. If this is one of those models, I've included the contact info below.
PlanetROI
Phone 1-844-433-8476
Email: Service@AcerRecertified.com
8:00 am to 5:00 pm M-F, EST time-zone
