virtualbox.org

Is this possible? I want to install a virtualbox of Win7 64bit, but It won't allow me. Is virtualbox able to do this? Am I doing something wrong to make this work?

A guest is called a guest or a VM. Not a VirtualBox. VirtualBox is the name of the application software, and your misuse of the word made your question confusing.

I believe you are really asking if it is possible to install a Win7 64bit guest VM running on a 32bit host. The answer is yes, provided your CPU supports VT-x, and you have this enabled in your hosts BIOS.

And the CPU is 64 bit capable. Early Core Duo CPUs were 32 bit only, but still had VT-x capabilities. The User Manual and VirtualBox FAQ both describe what is required for 64 bit guests (pretty much what Mpack said).