Glitchy lines seemed to have invaded almost all of my monitor, but the small section up top that isn't covered I can still interact with and even open the desktop icons that can be shown. How do I fix this?
Check the video cable on both ends. Make sure it's secure. Make sure the connector receptacle isn't loose.
Try a new cable.
Try the monitor on a different computer.
Lightly pinch the bezel (thumb on bezel front fingers on monitor back) all around the edges of the monitor to see if the visual issue changes in any way.