Most monitors normally display some kind of startup splash screen, or if the input is not seeing the video signal, a "No Signal" report before entering standby mode.
If the power indicator light comes on as normal, and doesn't indicate the monitor is in standby mode, but the normal startup screen doesn't appear, then the backlight not operating is the likely cause. Often in this situation if you shine a torch close to the screen in dim surroundings, once Windows loads you can faintly see the screen image lit by scattered torchlight inside the LCD panel.
It's possible that a backlight lamp is at fault, but more often the cause is the backlight inverter, which in most monitors is part of the power board. It may not be a difficult or expensive repair, but considering the low cost of reasonable monitors now, many people do use a fault as the trigger to update to a new unit.
Edited by Platypus, 19 December 2008 - 02:52 AM.