I used the disc with a generic key to install and my 8 key to activate. All went well but the cleanup system files will not close. It removes bits at a time but the fan is humming and it does not say successful or close. It does chip away so there are a few mbs left. I was hoping to close so I could image a clean OS with no defects. I ran the health DISM and the win update trouble shooter. Is this something to attend to before imaging?