Toshiba laptop has no display; won't boot

Registration date
Sunday September 29, 2013
Last seen
September 29, 2013
My Toshiba Satellite L670 laptop will not boot and has no display (2-3 years old). I tried a new hard drive but it had no effect. I have tried some of the suggestions offered on this site, such as removing the battering, unplugging the cord, and holding the start button for two minutes before reconnecting the cord and attempting to restart the computer. Nothing has worked. Any guesses as to the problem? Any suggestions for repairing the laptop?