Help Needed ASAP!!!

[Nhoechst]

I just drove my truck onto the driveway and not even a minute later I went to turn on my accessories and they would not work, I then tried to start the truck and it wouldnt even turn over. I checked my battery and it has full voltage, both grounds have full power, and I cannot figure out what is wrong. My father said it could be the ignition switch, but I dont think it can be that since the lights, radio, horn, brake lights, and wipers wont work either. I already sanded the grounds to be sure, and I also already tried to start it in neutral and change through the gears. Please tell me any info you may have, I am taking it to an important show tomorrow night and need to be able to take it there!!
Thanks for any help!!