OK I downloaded version 2015 and installed it this morning. I already still had sketchup 2016 installed (which exhibits the same slowness. sketchup 2015 also exhibited the same slowness until I installed an older version of the intel HD 4000 driver. Once that older video driver was installed and I rebooted, now both sketchup 2015 and 2016 respond normally. However, sketchup 2017 crashes immediately and brings up the bug track screen.
so I can work with version 2016…
thanks for your help and I hope this information helps others…