Hyper V Cannot be installed as Hypervisor is already running inside windows 8.1 ( which is a VM inside a windows 8 hyper v manager)

Hi, 

Although it is not concerned with windows server. Please help with this issue.

I Installed windows 8.1 OS inside Windows 8 using hyper V manager.

Then i installed visual studio 2013 update and i tried to run windows phone 8.1 emulator. 

It said, one of the hyper v components is not working correctly. So, i disabled and enabled hyper v features using "Turn of windows features on or off" settings.

But this time "Hyper V platform feature was installed"

When i hover my mouse over that it said "Hyper V cannot be installed: hypervisor is already running"

Please help me.