After trying the standard and much covered Power Reset buttons press (see Youtube.com) I still had an orange, flashing (slowly) battery icon. I did the reset three times and left it to charge overnight. Still no luck, so I unscrewed the bottom plate (how you access the battery) and installed an old but still working battery. My Roomba 655 then ran for 12 minutes, which is the length of the charge that battery holds. I have a replacement battery in there now and it WORKS!