MBP 2010 15" won't boot without disconnecting power and battery My MBP 2010 will only power-up if I disconnect power and battery, and then only connect power. When I shut it down, it'll only power up again if I remove the power first for >10 seconds.

I've tried an SMC Reset, a PRAM Reset, but nothing works unless I disconnect everything for >10 seconds.

It seems especially odd as even though it starts up the first time, it won't start up a second time without the complete power disconnect. Note, if i reboot, it restarts fine.

The battery is charging correctly, and I get the appropriate green/orange lights on the MagSafe.

For now I've left the battery disconnected, so at least I can work around this.

Any ideas?
Not sure what is going on, but, I've found that even though the machine looks like it is shutdown, I have to hold the power-button for 10 secs for force turn it off. After I've done that it starts up fine.