Hi. I recently bought a second-hand MacBook Pro (5,5 - Mid 2009) which came with Mac OS X 10.6 Snow Leopard. The previous owner had upgraded it to 10.6. The previous owner had changed a lot of settings and installed many programs, and I would like to restore all the settings to default and delete all of his programs. Would it be possible to do that without reinstalling OS X? The Mac came with an install disk for OS X 10.5 Leopard.