first, I moved your post to it's own thread as it just makes things easier.
If you had originally upgraded to Windows 10 correctly then you can clean install Windows 10 without having to input an activation key. When asked simply click I don't have one and you'll find the os is activated once you get online.
Before you upgraded did the laptop have Win8.1 Home or Win8.1 Pro on it? If it was 8.1 Home, then you can check your computer for W10 Home after the upgrade or clean install. If it was 8.1 Pro, it should wind up being W10 Pro after the upgrade or clean install. The new W10 should also show 64bit, as your laptop was 64bit prior to upgrading. Remember that windows upgrades via a "same-to-same" method. So, if your W10 Home or Pro shows up as 32bit and not 64bit, you probably did something wrong. You should then take it back to Staples and pay them to do the upgrade for you.