Firstly if it's just those two large wires, I'd recommend unbolting them (don't let them touch the body though - better disconnect your battery first
), cleaning the terminals, and tightening them back up. See if that gets you anywhere. It's possible the terminal on the power distro box is just worn out (or possibly broken, but you can check this with a multimeter)
Does it turn over when you try to start? If so you may want to check the voltage at the starter while your wife shakes the lead coming from the battery. If the voltage stays good there, I'd say the solenoid on your starter is bad if you can't even hear it click, and you'd need to replace your starter. You may also want to check the ASD relay in the fuse box.
Oh and it's possible you just have a bad wire somewhere - I know I've had to replace a number and they're fun to chase down; I love how they sold the wiring harness manufacture to the lower bidder
If you find yourself doubting the wiring get yourself a factory service manual (FSM) and a good digital multimeter and have at it