Power supply problem?

[glatt]

Turns out I either don't know how to use my auto ranging meter, or it's crap. It won't settle down on a known value even when I try it on a working battery.

So I wen old school and just bought a cheap analog meter from Radio Shack.

The green wire that runs the fan is at 4.0 volts.
The purple wire is at 4.4 volts.
The red wires are at zero volts.
The orange wire is at zero volts.
The white wire is at zero volts.
The blue wire is at zero volts.
They gray wire is at zero volts.

All measurement were on disconnected wires with no load. I think the power supply is broken.

How do I find a proper replacement? It's a Dell Dimension 8400.