ram1009 :
I change HDDs or SSDs frequently so what I would do is to use a new drive and a fresh install of W8. After W8 is up and running you can install your old drive as a second drive and migrate data at your leisure.
Just realize that I won't be able to do this, since I am getting the windows 8 upgrade version. Naturally I think it will only work on an existing windows 7 installation. I won't be able to do a clean/fresh windows 8 without losing everything, well......... unless I want to back up my stuff before installing windows 8 upgrade onto windows 7. I really don't know if windows 8 upgrade version allows you to do a fresh install.