Weird Problem

[Duality1]

Yesterday, I built my computer and everything was working fine. I managed to install Windows XP and everything was perfect. I turned it off, and the next day, the computer turned on but none of my objects worked. My mouse didn't work, my keyboard didn't work and my monitor didn't work. The only way I could make the monitors light go green was to press the menu button. I did that and it said it wasn't receiving a signal. This is very weird because I haven't done anything to the ports or anything like that. Even my cd drives won't open. They are receiving power but they refuse to open. Can anyone help me please?

 

[Inforcer]

Did you test the power supply unit to make sure it isn't malfunctioning? ie output power is what it's supposed to be.