Hi Albert,
I am Dave, I will help you with this.
There is no problem using 3 keyboards on Windows,
You would be able to press Ctrl + C on one Keyboard, and Ctrl + V on the other keyboard, that will work
However using keyboard shortcuts, you cannot press Ctrl on one keyboard and C on another, that will not work.
Because that you press keyboard combinations, there is usually only one instruction sent from the keyboard, and for Ctrl + C, that would be something like:
^{v}