virtualbox.org

I just installed VirtualBox 4.2.12 on Windows 8 Enterprise x64 but can't create / run x64 VM's. Anyone else the same problem?
I am not new to VirtualBox and using it for years, before it was from Oracle and even before it was from Sun.
But never had any problems with x64 Virtual Machines until now. The other strange thing is that Virtualbox limit the VM CPU's to only one.
Anyone else troubles with this VirtualBox build on the same platform?

Solved the problem.. It was Hyper-V. Even when you shutdown the service it still blocks the Acceleration features of VirtualBox.

You need VT-x in order to run 64bit guests. VT-x will only be available if enabled in your host BIOS and nothing else is already using it. In the case of a Win8 host the usual mistake is to leave Hyper-v enabled, hence something else is already using VT-x.