Replacement battery already dead?
I installed a replacement battery for my mid 2012 macbook pro and followed the battery conditioning guidelines. After I left the battery run out for the first time, it now won't boot under any circumstance.
I opened the laptop again and made sure the connection was good, but it seems that this battery is totally dead. Not sure what's up, because this is the second time i've replaced the battery in this laptop and the first replacement lasted years.