<VV> Blew the Electrical

[Western Canada CORSA]

The battery hold down on my RS came loose.  Allowing the battery to slide
and the positive terminal to contact the latch mechanism on the cover.  I've
replaced the chassis to engine ground, and borrowed a battery from Shawn.
 
With the ignition in the off position the stereo is getting power, unless
you turn on the lights, in which case the lights come on and the stereo goes
off.  The aftermarket stereo is drawing power from the cigarette lighter
prong on the fuse block. Turning the key to the on and/or start position
turns the power to the stereo off.  The engine will not start, no clicking
from the solenoid.
 
Any thoughts on where I should start looking for what got fried?
 
Regards,
Joel