Staff recently bought my MacAir , and saw that I had a way to install windows in him in a partition. I did the whole procedure just right and it worked . But after a few days just deleting the partition that was the mac os and now wanted to know how do I install it again and go back to using the Apple system. Does anyone know how I can do this procedure ?
Hold command-option-r when booting to get to Internet recovery. Once there use Disk Utility to erase the drive to Mac OS Extended (Journaled) format. Then quit Disk Utility and click reinstall OS X. That will wipe the drive and get you a default OS X install. Of course any data on there will be erased.