I have been using Avast free version with great success for some time on my personal laptop. I now need to do a little bit more with it. It laptop has Win 8.1 installed and now I installed Win 10 onto a second partition for business purpose. I need a lot more security for the Win 10 since I'll be inputting client information using that OS. Now I need to know is, do I buy an upgrade and install it into my Win 8 and it protect the both OS, or do I need to keep running the free one on Win 8 and buy the upgrade and install it onto the Win 10 partition? I also plan on encrypting the Win 10 partition for additional security. What's the best way to address this?