Screen flickering and horizontal dotted line on screen of my new iMac.
I have a new iMac for 2 moths.
This morning sudenly my Mac shows a horizontal dotted line (1 pixel), at the bottom of the screen, at 15% from the bottom.
Below that line, the image starts to flicker now and then.
There is also a vertical yellow line accroos the screen (1 pixel)
The flickering is very anoying, what can I do?