Install Virtual Box and Ubuntu on Windows 7

OBJECTIVE:
1. Download & Install Virtual Box
2. Install a Ubuntu server in the VM

ACTION
https://www.virtualbox.org/wiki/Downloads
Choose

• VirtualBox 4.3.12 for Windows hosts  x86/amd64

save VirtualBox-4.3.12-93733-Win.exe
run the installer - Done.

PROBLEM:
Get an error:
"This kernal requires an X86-64 CPU, but only detected an i686 CPU. 
Unable to boot - please use a kernel appropriate for your CPU. "
Grr.  Given that I have a 64bit hardware CPU but surely we are in a virtual world here and I would have thought it should at least pretend to be 64 bits or 128 bits if things were so wanted.  Apparently not.

SOLUTION
https://www.virtualbox.org/ticket/12350
Uninstall Hyper-V