Yes, you don't have to use Seagate's software. You can use the built-in Windows Backup if you wish, or even setup a Dropbox shared folder on that drive. Just access the drive directly from Windows, and do whatever you want with it (like copy your own files to it).

• Uninstall Seagate Dashboard Mac

Uninstall Seagate Dashboard Mac

So I could essentially drag and drop? And then remove all the Seagate software? Sure, as long as you can see the Seagate external drive as a standalone drive letter (like F: or something similar) and you haven't enabled any type of encryption, then you can drag&drop as many files as you wish.