Install - also install OS or not?

[theillustrator]

Hi,

I am new to Virtualbox.
I currently run Windows 7 PRO 64 bit.
I have installed Virtual Box and am now going to start a "New machine".

Will I have to install another operating system (as it is asked which OS I will be sing when creating a new machine), or will I be able to simply start without actually installing windows 7 again, but this time on the Virtual Box "New Machine"?

Thanks in advance
Stefan teh illustrator

[stefan.becker]

Every OS you want to start must be installed in VirtualBox. Please read the User Mnaul and some FAQs, that describes what Virtualization is and how it works.