Computer won't start after changed battery, but did start once.
Changed battery because original was discharging too fast. New battery showed low capacity (according to onboard System Parameters software) and discharged rapidly. Replaced with another new battery, used only two screws to hold in battery and two on back cover, went through Battery Calibration process, System Parameters indicated all O.K. . Installed all remaining screws, attempted to use computer, wouldn't start up. No front light, no fan, no nothing. Removed screws to duplicate last known good conditions, no change. Tried disconnecting battery to start up with charging cord, no joy. Tried various re-setting schemes with onboard keyboard, no joy. Battery voltage at first 9-pin motherboard connector indicates 12.36 VDC. Randomly checked a few solder joints on motherboard, 12.36 VDC. (I don't know what/where any specific test points are.) Battery charger showed orange for awhile, now showing green light. Have tried "Power Cycling" and "Resetting SMC" with onboard keys; no joy. Suggestions?! Anyone?