Unfortunately that's an "orphan phone" - pretty much made in and used in the Philippines - so not much is known about it by anyone who's not into cellphones in the Philippines. Hold the power button in (with the charger not connected) for at least 30 seconds. During that time something should happen. If not, it may have to go into a repair shop. But considering the price of a new one (1,500 Pisos), it probably would be a lot cheaper to buy a new one. But bring it into one and find out.