Locked out of my tablet—it's asking for a password I don't know. Help?

So, I just picked up this Dell Inspiron running Windows 8.1, and now that I've actually powered it up, I'm staring at a password prompt. The catch? The previous owner didn't hand over the credentials, so I'm basically locked out of my own purchase.
Is there any way to bypass this password, or maybe some other workaround to get past this hurdle?