Also if the power supply doesn't work why is or powering the monitor on to pc power saving mode :/
The power saving mode is for the monitor only. You could plug that monitor into to ANY computer that is turned off (or won't turn on) and get that screen. Your monitor is still GOOD.
do you know why it broke after keeping it off for a while?
It's a computer from 2003. They do that sometimes.
Some component inside the power supply failed after not being used for some time. It could have been a power surge/spike, or it could have just been due to the fact that it is quite old for a consumer power supply unit.
If you were already thinking about replacing the computer now may be a convenient time to do so. Hopefully you will have better luck with your new computer!
edit: replied to both posts
Edited by bcohea, 08 April 2010 - 08:09 AM.