To install madVR on Windows 8.1 or Windows 7 please visit this link and download the files:
Once you have downloaded the file, create a new folder under Program Files, or really anywhere you want to, the location doesn't matter, but you will want to put it somewhere safe so you don't accidentally delete the folder.
After you have extracted the .zip file, navigate to the folder and run "install.bat". Make sure you run as Admin. After that is done, you should be all set. Now it's time to enable madVR for mpc-hc!
Configuring mpc-hc to use madVR
If you have not already installed mpc-hc (Media Player Classic), you can do so by visiting this site: http://mpc-hc.org/