ACER M8 Black screen

My acer M8 has a black screen problem...... when powering on the device , the device just vibrates and nothing happens. when i plug the device to a wall charger a Blue LED notification appear i don't know what it means...... i have tried to flash a stock ACER M8 firmware the flash process is success but the problem of the device is still the same, it just vibrates when powering on i have tried to enter on recovery mode but then again nothing happens