So this time the problem started out as a simple issue. Whenever I bump the desk or move the keyboard out with too much force, the computer shuts off. Everybody told me that it could have been a loose connection so I checked it all and replugged everything back in. The computer starting working fine for about 5 hours then it just shut off randomly while I was playing a game. This time, though, it shut off without me bumping into anything. SO, is this a power supply issue? I'm using a 550-watt supply while running a 7800 GT. This is the right power amount so that's not my concern. And now the problem has gotten worse to the point where I turn on the computer and nothing shows up again. Windows doesn't load and the screen is on too. You here the fans and everything but nothing will load. All my parts from my old issue were replaced EXCEPT the power supply and CD-drive. I don't think it could be another loose connection b/c now nothing even shows up. Please help!!!