I'm trying to dual boot a macbook pro, but it is too old to support a usb as a means of install and I don't have the full install disk, only the upgrade. I have an iso of Windows 7, can I somehow run a virtual box of a partition I put on my hard drive, and run the iso to install Windows? I'd like to be able to do that and then stop the virtual box, and be able to boot to the partition. Is this possible?
What you describe is not possible.
Virtualbox runs inside your operating system (in its own window) and cannot boot partitions, and does not have its own 'boot menu' like GRUB that installs on your machine. It CAN boot an CD/DVD/ISO Windows install disc that you have. Virtualbox also makes a virtual partition so you don't have to worry breaking your current system. However, running two operating systems at once may be too heavy for your system to handle, and there is really hardly anything you can do about that besides overclock or upgrade.
Hope I have helped you.
PS I do not condone piracy. I hope you got that ISO legitimately.