Power goes away when i turn key

I have a 94 Grand Cherokee Laredo, 4.0/6. On Friday as I was getting out of the truck I heard a ticking in the glove box, then about an hour later when i got in to go out, when i turned the key all the power went away (no beeping from key in ignition, no radio, dash, dome, NOTHING). So i thought it was bout the alarm because of the ticking & had the factory alarm removed, but still no power. The alarm guy said that everything is getting constant power and it is either the igition switch or the computer fried. I can get the power to come back by disconnecting the battery for a couple hours then reconnecting it, but when i turn the key it all just dies again. Im hoping its just the ignition switch & it didnt fry my computer. Anybody have any thoughts before I buy the switch??