Over the last week or so, since about 23nov2017, Windows 10 updates have included a broken version of the ATI Radeon HD Series 4600 driver. Once updated, multiple displays don't work, and the correct screen resolution is not available. The workaround is to install the previous driver, from October 2015, and then to disable automatic driver installation. Of course, I would prefer not to disable this, but the latest driver needs to be fixed. Who should I contact about this? I am running on a Dell OPTIPLEX 960, about eight years old, but it's high-end and still works very well. 8GB, 3.16GHz.
To quote Francis Bacon "Never was knowledge delivered in the same order it was invented." That is, the above statement of the problem took several long, painful days to identify -- originally I thought it was a hardware problem. Etc., etc. But it's just a broken driver.