Right melv are you sure there is no power supply issue, have you looked very carefully to see if the screen is lit but very faint? (you need a dark room to check that). Then unplug all usb or external outputs (speakers, monitor card readers etc. After that yo can try booting up in safe mode. To do that switch off and wait a few minutes. Then switch back on with the f8 key pressed and see if the menu appears to give you the boot up in safe mode. Also have you installed any new apps or programmes recently. Also can you hear the fan and hard drive kicking in when you press the power button? Lots of questions I am afraid.