Hi. My name is***** you for your question and the opportunity to assist. Give this a try. With the laptop running, hold down the power button until the unit shuts down. Till all the lights go out and you hear the laptop shut off. Then unplug the a/c adapter and remove the battery. Hold down the power button for 60 seconds and release. With the battery out, plug in the a/c adapter and start the laptop.
If the light is still flashing after startup let me know the model number of the laptop. I'll have to look up exactly which light is flashing and what it indicates.