If you seriously think banning all guns will solve anything, you are seriously misguided. Our idiot stick prime minister banned hand guns (among a few others) after a shooting in the USA, and guess what... We still have some gun violence problems here in Canada because the gun problems we have here have never been related to legal guns or legal gun owners. In every case in Canada, the problem has been illegal guns acquired, often by people who are under court order not to possess such a weapon.
So to be clear, banning guns is not the answer. Now, that being said, a lot of the gun violence problems that you seem to have in the United States do seem to be with legal guns. Tightening laws to restrict them (such as requiring a psych evaluation to get one) but not necessarily ban them outright will help to go a long way, however it will never solve all of the issues. It will just make them shift more towards illegal guns and illegal gun owners, which obviously the law has done nothing to prevent.
Also to be clear, I am saying that there is a difference between gun control and gun prohibition. With proper gun control, the number of issues that you're having down there in the USA would dramatically drop, however would never go away completely. Gun prohibition on the other hand never has and never will do anything to curb the problem.