VirtualBox OSE conflict with KVM

When starting virtual machine, VirtualBox will give error status:

"Failed to start the virtual machine XYZ

VirtualBox can't operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot.
(VERR_VMX_IN_VMX_ROOT_MODE).

 There are different ways to solve this;

1. In terminal type : modprobe -r kvm_intel   
2. Remove kvm and Qemu kvm through terminal

$ sudo apt-get purge kvm 
$ sudo apt-get purge qemu-kvm    

The two mentioned above will either unload the kvm modules or   remove them totally from your system.In case you don't want to remove kvm from your system and still use Virtualbox (though this would be hardly the case in my opinion)

modify /etc/init/qemu-kvm.conf :

 $ vi /etc/init/qemu-kvm.conf  (This step needs to be performed by the “Root” user to be successful)

 

Change ,

start on runlevel [2345]
to
#start on runlevel [2345]
 

effectively disabling this line.

Run;

$ sudo initctl reload (This too requires sudo privileges) afterwards to reload the settings.

This should make the kvm module loading manual, with modprobe or with
sudo stop qemu-kvm
and
sudo start qemu-kvm