The batteries are pretty new. This is the Maemo 5 OS; I'm on a public Windows 8 Pro machine. The Flasher I was going to use is the 'flasher-3.5 for windows', I was following one of this site's threads. I'll need to read-up on flashing and will try the wall-charger and command-line next week.
When I hold down the u key and connect to the PC, the bright orange LED and unlit 'NOKIA' logo and a USB-symbol come on continuously, I guess it's charging; the PC recognizes it as a Nokia "Wireless Communication Device" in 'update-mode' and says it has the right drivers.