A mainboard fault. Yes there is an OS setting but we can test for that by trying to boot Windows after a shutdown but I see no reason to explore that. Sorry to read about your loss.
Bob
My Dell Latitude D620 had been running fine on both AC power and battery, although I have primarily used AC with a docking station. Now I've found that although the battery appears to be 100% (and I even occassionally get an indicator that it is 98% and charging), I cannot run at all on battery power. The test lights on the battery itself all light up. It is a Dell battery (Type TC030), and both AC adaptors and the docking station are Dell (PA-10 for the docking station and PA-12 for the laptop AC). It seems as though the laptop recognizes the battery, and charges the battery, but won't use the battery. Any suggestions?

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