Q: iTunes does not automatically sync and backup my iPhone when connected

Even with the 'Automatically sync when my iPhone is connected' option ticked, my iPhone 6 with iOS 9.3.2 still does not sync and backup automatically when I connect it to my Windows 10 PC. Before I reinstalled Windows on that PC, my iPhone automatically synced and backed up to my PC whenever I connected it. I tried searching for the problem online, but what I got was people asking how they could disable automatic sync on iTunes, something which doesn't happen in my case. Any answer would be greatly appreciated, and thank you.