Which Library? If it's the user library then you can just create a new user account and migrate your data over to it. It's safer and quicker.
If you really want to reinstall OSX, then I recommend an Archive & Install because theoretically you won't lose any data. It'll put your current system aside and install a new one next to it. You can then navigate your old system like any folder in OSX and get any necessary data back from it.