I'm out of the loop on Saturday (coach 3rd grade b'ball team and laying wreaths on vets graves) and Sunday is a Steelers' game (). I watched a Youtube video and it doesn't look too hard (if I can keep it all straight). I might take the box to the bench upstairs and see what I can see. If it looks doable, I'll buy a power supply and have at it. If not, I'll be in touch. Do you have a favorite place to buy a power supply (BB, Microcenter, etc.)? Video indicated 650W ought to do the trick.
Take a picture of the inside so you can see what needs a cable going from the power source. I worked assembling computers during the summer in high school, it's just plugging in cables - it was a minimum wage job with five minutes of training- nothing difficult