Macbook Pro X icon, battery indicator does not glow LEDs either

I have the same problem like may others.. X icon.. Battery indicator LEDs are not showing anything..

we might think battery is bad.. but while booting with AC adapter.. if I remove the plug.. it boots and work with battery fine.. but if I reconnect the AC adapter it goes to sleep mode or maybe just LCD shuts off.. I'm sure of it.. im using mid 2009 version and I'm getting a 3 1/2 hrs backup until yesterday..

I was replacing corsair RAM 8 GB one and for the battery connecter.. I use flat screw driver (metal one) to lift it.. saw a tiny spark then(logically since the battery connector is female type, I thought no pins protrude out, spark is static).. physically everything is fine.. except I need AC adapter to start the laptop.. I wonder if we'll get the exact reason of this anytime..

By the way tried everything.. SMC, NRAM.. those things etc.. nothing solves.. just learnt living with it..

Any suggestions except Apple care and logic board replacement guys.. Also I'm thinking all facing X icon should test the AC adapter removal during boot test to see if battery is fine.. buying a new one for test is waste fo money.. hope this helps in throuble shooting for someone that can save money..