Alienware M17xR4 Disabling the Integrated Graphics Intel HD4000 and use only AMD Radeon HD7970M.

Hi,

I want to disable my integrated Graphics Card Intel HD4000

and I want to use only the AMD Radeon HD7970M as I was doing every time

by using the FN+F7.

For some months now it doesn't work and I don't know why.

I Uninstall both Graphics Drivers and Reinstall it with newer and older many times but still doesn't work.

What is the problem?

I try to find some videos on YouTube and hasn't any information there.

Any help, any suggestions?

Please !!!!