Let's say theoretically you ban all guns and not even the criminals have them anymore. Do you really think that is going to stop someone from committing violent crimes? "Oh I want to rob this store but I don't have a gun. Guess I will just have to sit this one out."

A gun is just a tool. You know how easy it is to make a homemade flame thrower or convert a few simple devices to become deadly weapons? Where there is a will, there is a way, so there really is no point in imposing all these restrictions and anti-gun legislation. In the end, it's only honest people that suffer.