Computer boots, but screen is black

Hello,

yesterday my computer worked fine for most of the day, until the evening, when i headed upstairs and shook the mouse for the amber light to go away. it did, turning black as per usual. i sat for about 3 hours total, waiting for it to load, but nothing came up. occasionally there would be a quick flash of white before it turned black again; these flashes are not unusual for me as i sometimes get them regularly. after 2 hours i pushed the monitor button again - no green or amber light, no flicker, nothing. i wait another hour - nothing.

eventually i decide to flick the power surge off. i turn it back on, press the computer on - i'm used to the clicks of my computer so i know that, indeed, the computer itself is perfectly fine. still, no logo and no light on the monitor, though.

the cords to the monitor seem to be connected firmly and properly.

i have a windows xp computer and a dell lcd monitor. any ideas?