It should be noted that while reinstalling OS X System Software on a Mac with Recovery Mode is the preferred method (since it only installs the CURRENTLY running OS files, rather than an Internet Recovery install which will install the OS that shipped with the Mac originally), if you're performing this re-install to solve a problem, you MAY be wasting your time.
Many times, the problem you're having may be tied to a preference file, daemon, or other app file from a third party app, which will still be there unless you do a complete clean install as maflynn mentioned above.
Still, reinstalling only the current OS files is faster than completely backing up the computer and starting over from scratch.