How-Do-I-Re-Install

how do i re-install. becuase i accidently deleted the file where the pics get saved and i took it out of recycle but its not saving the pics anymore even when the file in on my desktop.so when i take a pic it goes to oblivion.plz tell me how to re-install or un-install or tell me another way to fix it.and if i un-install, how do i install again.