monitor turns black with the monitor on/off button light ( green) goes off-Then if I hit that button once or many times, the green light is back On and screen displays again. Is this something to do with the back light of the monitor-How to fix or replace it. How much does it cost the backlight. Monitor was bought 3 yrs ago in toronto, canada-from canadacomputers.com store. Warrranty period is gone. Thank you so much.