Pretty much as the title says. The scenario is pretty much, brother's friend is giving me computer parts, so my brother told me to move my computer to the kitchen so he can put them in. So I turned off my computer, flipped the power switch and unplugged everything and did as he told me. But when we put it in the kitchen, his friend wasn't here yet, so I decided to plug everything back in and play it for a while till he does. But when I did so, and flipped the switch on and turned my computer on, everything ran like usual, but the monitor wouldn't come on. We switched monitors to see if that was the problem, but the problem still consisted. We were going to try different motherboards, but my Power Sluppy doesn't have all the plugs required. And we would try different video card, but both my brother's requires 550w and his friend's require 600w. Sad thing is, my Power Supply is 450 max. I might have said some things wrong, because I'm not much of a computer tech savvy person, but any help would great.