My beanstalk neo has two lights on top a blue one and a yellow one?

normally when the computer runs the blue light glows followed by the yellow light then the computer starts. But now a days the blue light only blinks just once and the computer does not start. Sometimes if it starts , while booting the screen becomes black and only the yellow light glows steadily. wat is the prob i cant understand? and also is there any provision in beanstalk that it will switch off if it gets heated more?????????