So...
You should be able to see the battery wires on the side of the keyboard. The laptop powered up fine without the battery connected, though windows thinks the laptop still has a battery.
I would suspect you have either a power issue on the board or your power supply isn't within spec.
The power supply should be 19.5V, check it with a multimeter and see.
I would bet that if the battery was charged the laptop would power up.
Remember G46's use Optimus and it's very finicky, it takes about 18-20 secs for the machine to post.
Keep this in mind when troubleshooting.
Also keep in mind that the 40 pin cable that connects to the keyboard assembly is very fragile. Check the cable ends if you've recently removed the cable.