SMART ALX: I assume you find it OK for your monitor not to turn on. :))

Pedro Martínez:It's going to get returned on to it's original factory setting.

SMART ALX: you probably get no signal from your computer
try the monitor on another computer to check the monitor itself

if it works try another cable between your computer and your monitor
if that still doesnt work then my guess is that your graphics card is broken :(

SMART ALX: Check also your current supply. I had this happen once, I thought the central unit is out for sure, but it turned out simply to be a badly plugged cable. The monitor would react to a low current, but the box won't.