Sorry I haven't been here. Christmas and New Year's holidays plus a nasty flu bug have kept me from doing much of anything. I thank everyone who has contributed their experiences with this problem. Thanks to Topaz for working on a fix. I ended up uninstalling 1.6.10 and installing 1.53 which worked the way it should. I'll try 1.6.11 and see if it works for me. Thanks, again.
For the record:
AMD-FX 8150 Eight Core Processor
32 GB DDR3 G.Skill Memory
GeForce GTX 970 4GB Driver v. 388.13