I'm adding a ssd before July 29th for the OS, the only concern of mine is erasing the files on my Hard drive. What im planning to do is before the release (July 29th) I'm going to reinstall windows 8.1 on the SSD. Then attach the Hard drives like it was out of the box instead with files from windows 8.1. I'm guessing that i have to erase the disk manually or will windows just do it for me? Any other better suggestions would be nice to know