Installing two operating systems and then dual boot your machine. This is to put more than just Windows and Linux and OSX on the same machine. Another option is a virtual desktop option. This video will guide you through the steps of setting your computer up to boot two different operating systems.
The links used in this video are: Gparted - http://gparted.sourceforge.net/download.php Wubi - http://www.wubi-installer.org Boot Manager - http://gag.sourceforge.net