I recently got an SSD and to make room so I can transfer my files onto it, I was deleting some things and I guess I deleted something that I shouldn't have. Now Windows won't boot on my hard drive. I found a Windows 8.1 disc and put it on my SSD but I don't have an activation key for it and I'd really like to be able to use the activated Windows that's on my hard drive. So how do I repair Windows on a drive that's not the drive I used to boot?