Thank you for your thorough response -
I downloaded/installed 12.1, rebooted, no change.
I have an Asus S405C laptop, as best i can tell it has an Intel HD 4000 display adapter (vrs. 10.18.10.3308).
After going through both Intel and Asus driver downloads, I got a message that the drivers I have are newer than what Asus has on their website.
Intel has a more recent version, but after downloading gives a message that the driver needs to be from the computer manufacturer.
I only see the Intel adapter, no other (doesn't appear to be dual adapter).
Any ideas after this?
Thanks