Hello, I just built my new PC and booted it off the Windows 8.1 OEM CD. I was going through the steps of installing Windows but when I came the selection screen when I am supposed to choose what HDD I want to use I click my 1TB one and it won't let me click "New"? This HDD was on my last PC but I just clicked the format button because there wasn't anything important on it. How do I continue?