I finished building this robot April 21, and it worked fine.
The next day, I decided to tidy up my file system, then removed, and reinstalled Arduino.
Now, the Blink program works.
The BYFR_ServosOnly program works, with the exception that it goes only in reverse, and does the turns, but never goes forward.
The popmech_robot-10 either sits motionless, or goes in reverse. When it is going in reverse, the switches make it turn, then go in reverse. It never goes forward. This is similar to the ServosOnly, in that it never goes forward. The remote has no effect (IR recvr re-tested).
I have checked all the connections.
Any suggestions appreciated, Don Oliver