Solution: I tried everything: GL, driver, I think everything mentioned above. Finally, I did find a solution, for which I am thankful to God.
Run Sketchup in Compatibility Mode. It worked when all else had failed. And continues to work!
I used Win 8.
You can do the whole thing from a right click on the shortcut to Sketchup (or the .exe I think as well). I also found that running the Compatibility Troubleshooter, along with then running the program As Administrator, brought the speed of the Select tool back to what it should be.
