Will not power on

hi, I recently starting having battery problems in that it would not hold a charge more than a few hours. I tried resetting the SMC and and NVRAM and not the unit will not even power on. There is no LED on the Magsafe connector, however the battery shows a full charge (all LEDs lite) when button on left side is pressed.

I opened the unit and disconnected the battery and left sit overnight (suggestion from Internet) and still no power on. Do you have any ideas of what I might try next or can you provide an estimate on repair charges?

Thanks