I have a MacBook Pro that I received from a relative. He needed to retain the hard drive that was originally in it. So I replace the hard drive with one that I had already with Windows on it. I have no desire to use window, I just need to know what I should do to erase that hard drive and repartition with A Mac OS. I downloaded a copy or sierra from my pic using Trans Mac once and Power IOS once. The System doesn't recognize theDVD disk nor does it recognize the USB stick. How do I go about erasing this drive with the Mac? Every time I try to do an internet boot and recovery nothing happen and it goes on and tries to start the system using windows that's on the disk.