My Sony Ericsson K770i phone

Question

My Sony Ericsson K770i phone won't turn on. When I push the power button, the little light in the top right corner of the phone (above the screen, to the left of the "Sony Ericsson" logo) lights up red for a few secs and then stops. When I press the power button again, it flashes red and then stops. The battery was half full when I turned it off just a few mins befor trying to turn it back on. Please can you help me. Thank you!