Sigmatel S90 dead

Question

My sigmatel S90 had Airplance mode problem which i tried to rectify by resetting the eng. unfortunately due to low battery my screen blankedout. Now the phone is completely dead except when i press the power button the keypad lights blink. I tried pressing the power button for more than two minutes some times which of no use. Can anyone suggest a solution ? Deva........ [e-mail]