Re: 1st post....1st major problem :( (longish)
From what you described, Look inside the 20-pin connector and see if there is a connector that is bad, and you might just have to fiddle with it.
Along with the bad wire, since you were messing with things while the Power supply is on, you might have shorted out the board. But that is also unlikely.
A third idea: you might have knocked a jumper off or something, because you said that when you touched a part the light came on, it might have been using your hand/finger as a connector... Just a thought, so look where you touch to turn it on and see if two little parallel wires are sticking out, you might just need a jumper.
Other than that, i don't know, before throwing out the Power supply though try a power supply that you know is good and hook it up to your computer, if it works, the Power supply is bad. If you know that the power supply is good, and your computer still doesn't turn on, you know there is no power going into/through the motherboard, which means it needs replacing.