i have today the pleasure of working on a thinkpad 770...
It sees the battery in the littled led console, and windows (100% charged), it will run off the battery if i unplug the adapter, but it will not boot off the battery only...

side note, it was brought in for not holding BIOS settings, but that is not something i can reproduce now that i have set the date/time...

I was wondering if anyone had an idea what this might mean... I have been thinking the battery itself might be flaky, unfortunately i do not have a similar one to swap with...

thanks.