Install Linuxmint in Sun VirtualBox in 3 quick steps (with screenshots) - Step 3

Step #3 How to Run Virtual Operating system after installation

Read Step 2 before you follow the instructions mentioned below.

>>Reboot the system and Login screen appears or other way around is to select your system from the list and click on start. Enter your username and password to login. That’s all Enjoy:)

first boot after installation Welcome Login or GDM screen Linuxmint desktop after complete installation 

NOTE:One can even install windows and other popular operating system on Sun VirtualBox provided your PC has enough free resources, like ram, memory etc.