Computer doesn't work after crash/burning smell

I was browsing websites on a four year old Dell Dimension 4700 PC when all of a sudden the computer suddenly turned off. The computer would not turn back on and the power light on the front of the computer, which normally is green when the computer is on, blinked yellow over and over again. After unplugging the computer and plugging it back in, the blinking yellow light went away and the computer did power on (complete with green light), but there was a horrible burning smell coming from the machine and nothing loaded. Every time I try to turn on the computer now all I get is that green light and an incredibly loud fan, nothing comes on the screen, I hear no beeps, nothing.

What could this possibly be and what could I do to fix it? Thanks in advance.

 

It is most likely your PSU (Power Supply Unit). DELL uses very cheap units that are prone to go bad after a few years. The blinking orange light points to this as well.

The smell will probably be strongest at the top of the case where the PSU is located. IF you feel a need to confirm you can remove the PSU and open it (4 screws or so) and look for a bad capacitor. The little cylinders that look like this. The tops should be flat. If you are smelling yours it is probably obvious that one is bad. You need to replace the PSU.