The original 2010 Pro battery finally gave up the ghost. While the Mac help desk diagnosed a bad hard drive, replacing with a new one did not help.
After spending $100 on an online site (known to all) for an off-brand battery, which never charged properly, turns out the charger was malfunctioning. Purchased a replacement charger and THIS time I wanted an authentic Mac replacement battery.
Like a dream. The new battery from iFixit arrived 3 days after order and with the working charger performed as designed.
I have to admit: This repair job was like falling off a log, once I had the properly working parts in place.
Don't violate Occam's Razor; make sure you resolve the simplest issue first.
On the bright side, now I have two hard drives, one to serve as a backup device.
Oh yeah: Go to iFixit first. This is an outstanding company supporting the DIY community!!