Is there a way to connect and control motor shield board WITHOUT Arduino at all. can i connect it directly to my PC ? i'm getting confused since i red lot of topics that people use existing pins on motherboard.
This superuser post might help.
Raspberry Pis have GPIO pins that you can use to communicate with a motor shield, but regular (intel-based) PCs usually don't. In any case, you wouldn't want to mess with motherboard pins anyway; a short circuit might easily fry your computer.
However, this wouldn't be any simpler or cheaper than just using an Arduino.