FYI all.
I would get an error indicating that the loop() function was duplicated in a linked lib in the basic Blink program and get a compile error.
Changing the loop() to loop1() would avoid the error allowing the upload to the Uno but the program never ran...even with a serial monitor output in the Setup() function...zippo
Solution...go into the boards mgr and select version 1.6.21 of the Uno and install it.
Oddest thing...a fresh Arduino IDE install on another Win 7 64 system had no such issues. But my older install on another win 7 PC seemed to have some kinda remnant issues even after removing and upgrading.
^