Backup your entire drive

 Before making any substantial changes, it's always a good idea to back up your data—and that goes double when you're messing with your drive. If you have a backup tool you really like, go ahead and use that. I also recommend cloning the entire drive. That way, if something goes wrong, you can restore an exact image of the original drive and try a different approach. For this process, we've found DiskGenius to be one of the few free options left.