so i have recently purchased this table and computer that came with it. Mach 3 was already downloaded into the computer along with a program called q-cad. i think that mach 3 is set to recognize a cnc router not a plasma due to the fact that the g-code comes through with a z axis movement of 100, which just makes my stepper motor bottom out and made bad noises. im thinking that there may be something simple to change somewhere that i am just missing but with that said, i am most certainly missing it haha. any help and suggestions would be greatly appreciated as i am totally new to this cnc world. THANKS

Mach3 just works on the Gcode that you give it.
The excess Z axis movement which you describe is presumably being put into the Gcode which you have created from your Q-Cad drawing ?
If that is so then this is the area in which you should be looking. See if you have a Mach3 friendly, Q-Cad (or whatever you are using to create the Gcode) post-processor, intended for Plasma.

Tweakie.