Ok so, someone gave me a laptop to fix, which included the hard drive to fix it. I put the hard drive in, booted it up and then came to the Checking Media [Fail]. Doesn't it mean there's wrong? Do I need to reinstall the OS? The reason why I don't think it's broken is because I ran the built-in diagnostic application and it came back with the hard drive being just fine. I'm at a brick wall right now, any help is much appreciated.