Downloaded Xamarin Android Player and with >>next>> progress installed Virtual Box.
When I tried to start an emulator I got
Failed to initialized de
I had to turn PAE/NX off and then back to on...voila !!
It is a RAM related issue. The documentation is self explanatory:
You are trying to allocate >3GB of RAM to the VM. This requires: (a) a 64 bit host system; and (b) true hardware pass-through ie VT-x.
Fast solution
Allocate less than 3GB for the virtual machine.
Complete solution