Running VirtualBox on a Windows 8.1 host

I have a Windows 8.1 Pro 64-bit machine, with an Intel Haswell i7 processor, and 8GB of RAM.

I installed the latest VirtualBox (4.3.6) and I'm trying to install a Linux guest. I've tried several Linux distribution ISOs (Mint16, Mint16-xfce, Fedora20, Kubuntu13.10), and they all get stuck right after the Live CD boots. I managed to install some of them on my VirtualBox on the Mac, so it's not the ISOs fault. Something is preventing the boot sequence. Any ideas?

Finally found the answer. It all hinges on Hyper-V and the fact that it's enabled by default in Windows 8.1 Pro (as well as in other Pro and server Windows versions). With Hyper-V running, other hypervisors (like VirtualBox, VMWare and Android emulator) are crippled.

You could, potentially, disable Hyper-V from the Windows Add/Remove Features dialog. But what if you use Hyper-V for development or testing (i.e. WP8 development)?

The solution is to boot Windows with Hyper-V turned off. And the easiest way to do it, is to create a new boot configuration, with Hyper-V off, and boot to it whenever you need to use VirtualBox.

There are several step-by-step guides on how to create a new boot configuration - this one has some screen shots.