I have a Dell Dimension 8400 Windows XP Media Center 2005 computer, I disconnected the computer to blow the dust off the computer. When I went to hook it back up and turn it on nothing happened. The computer would not turn on. I open the computer back up and checked all the connections and everything is hooked up fine. A while back the power button (the plastic part that is pressed into the machine) broke so that when tilted to the front it falls out of the hole it sits in but it still worked. I don't know if this is the problem or something else like the power supply. Could you please help me?