Hello,
Let me preface this with I am a first time VEX/ROBOTC newbie. So this may be a easy fix.
1. built the tumbler
2. went through and downloaded everything in every way(USB/VEX NET, Tether cords,) all with horrible sucess.
3. The weird thing is that if I plug in my battery ALL of my Wheels/motors spin full speed and I dont know how to make it stop
4. I there a way to erase everything and Start all over?
5. how do you erase every thing down to the firm ware

There is a bit more information we will need before we are able to help. For instance, when you say that you had horrible success downloading everything, what specifically do you mean by that? Were you able to download the firmware, the code, did you get any error messages, etc?

Also, what you are saying in #3 leads me to believe that you have the motors and servos plugged in the wrong way. If you reverse the way the wires are plugged into the ports, the motors and servos will move on their own (and continue moving) as long as you have a power source attached. Make sure that the wires are plugged in correctly; the Cortex and its motors/servos are keyed to help with this.

If you can post your code on here using the [code][/code] tags, this will also help us to assist you.