iReboot

iReboot is a small but powerful tool that helps you easily switch between multiple operating systems on your computer. After installing iReboot, an icon will appear in the notification area. When you right-click on it, a list of all installed operating systems will appear. Just select the operating system you want to switch to and click the "Switch" button.

iReboot is very easy to use and doesn't take up much disk space. It is also completely free. So if you have multiple operating systems installed on your computer, iReboot is a great option for easily switching between them.