Most of the time I use VirtualBox to run Linux distros like Ubuntu and Debian. At the same time, I have to work with Windows Phone SDK which needs Hyper-V to run the Windows Phone emulator. Understandably VirtualBox and Hyper-V will not run at the same time. The easiest way I found to solve that problem is creating a dual boot configuration where one of the boot options has Hyper-V disabled. Here is how to do it:
This post is about using Oracle VirtualBox to install a Debian 7.2 x86_64 guest virtual machine on Windows 8.1 host.