My nephew played with my keyboard and he messed with the keys.

I have a Ibuypower keyboard and my nephew (3) came over and played with the keyboard. He likes hitting random buttons and the pc was on while he was doing this. Now whenever I try and type something, my keys will type multiple letters instead of one and it has made games like GTA unplayable. It has become impossible to do things like drive or get a gun and I don't know what to do. Is there anything I can do to fix it or should I just buy a new keyboard?