Lets say that a code is already uploaded to an Arduino Board Does The Computer It's Connect too need to have the libraries installed or are they not necessary?
The libraries are used only to compile the code at the time you're uploading the code.
After that, all the computer it's connected to needs are the drivers (not even the IDE, necessarily) - assuming you want it to communicate with the PC over serial; if just powering it, you don't need anything.