A few months ago I bought a Dell 4700 off of a friend for $30. It worked great up until a few weeks ago. Everything was normal, I turned it off, but then the next day it would not turn on. Instead of the two normal green lights in the front, there was one orange one. Not blinking. I tried removing cards, RAM, CD and DVD Drives, and even replacing the hard drive. Nothing worked. I now believe it is either the motherboard or power supply causing trouble, but as much as I would like to, I barely have enough money for one. So I really need to know what's wrong before I spend any money. Any ideas?