3ds Max shortcuts not working?

I accidentally the whole program by clicking a button (can’t remember which one) and now F3 and F4 (used to toggle wireframe etc.) no longer work. Help is needed.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.