Problem in laptop

Hello, my dell laptop windows 8 is not properly working. at times it works fine but sometime it doesn't start properly. as i start it after 3-4 sec the screen turns black and not any icons appear on screen except the curser. shutting it down is also aproblem .it doesn't shutdown properly as the screen gets off but the lights remain on. my laptop is just 1 year old .pls help me.....