Personally I would connect your new drive as master and on it's own, fdisk and format the new drive, install a fresh copy of Windows operating system onto it, together with any programs you use.
Once up and running reconnect you old drive as slave and simply copy over any files/photo's or music you want to save using windows Explorer.
Then format your old drive and use as useful extra storage.
Guys I know there are easier methods, but this way you end up starting fresh with a clean fast reinstall.
Martin
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