How do i fix a door knob?

ok so i was locked out of my house so i went inside through the basement unlucklly i found that the basemnet door was locked, the doorknob had a little hole which i insterted a nail into, i hit the nail with a hammer and wa la the door opened now the door wont lock again, i can turn the knob normaly but the locking mechanism only works if the knob is turned