VirtualBox is our favourite virtualisation program, but it needs to be properly installed with Windows kernel drivers and system services. Portable VirtualBox lets you install VirtualBox on a USB drive or external hard drive so you can run your virtual machines anywhere.
Portable VirtualBox is really just a wrapper for VirtualBox, designed to run on Windows host PCs. It will install the necessary files when you run it and uninstall them when you're done. That means you still need administrator access to the computer, so it isn't truly portable in the most traditional sense -- but it's still useful.
After you download the installer, you just extract it to your external drive and it will automatically download VirtualBox's files. Then, once it's finished unpacking the files, it will open up the VirtualBox Manager. From there, you can create and run your virtual machines as normal. Hit the link below to download it, and check out a full guide on using it at the How-To Geek.