Regardless if the computer is already in a Windows or MAC operating system, you must do the following to switch the OS:
- Restart the computer
- While the computer is restarting. hold down the "option" key on the keyboard until the screen shows the images for both the MAC and Window OS
- Click on which operating system you would like to boot the computer
- The computer will then load that operating system and you can log in like normal once it has loaded
