Best way to upgrade to an SSD:
1) Back-up the data you want to keep (Preferably to external storage)
2) Plug in your SSD
3) Plug out your HDD
4) Install your OS (with only your main disk connected)
5) Plug your HDD back in
6) Format your HDD (Make sure you have al data backed-up on another drive before you do this)
Windows files aren't usefull for anything if you have already installed a working Windows system on your new drive.
The reason why you have to only have your main drive plugged in while you install Windows, is the fact that Windows installs sometimes use your other drives for some Windows files. So when you plug out your secondary drive, Windows might not be able to boot anymore. I have had this problem before
Okay thanks a lot. for number 6, if i understanded correctly, i back it up then format it?