You can move AD to a new server by installing a new server and promoting it to a DC. What you then must do is move the FMSO roles from the old server to the new server before you dcpromo the old server out of the domain this will work. If you don't move the FMSO roles before removing the original server you will never be able to install exchange as it won't be able to contact the Schema Master.
What is the FMSO roles ? What does it stand for and how can I move them ? Also,I am replacing the old server with a new one with different hardware.