A Fedora Core hard drive I aquired

So here's the deal: My brother and I both have exactly the same model of laptop.  My brother, a very clumsy man, broke his laptops monitor, and continued to use it attached to an external monitor.  Recently we aquired a third laptop of the exact same model from a friend of my brothers, which did not function.  For whatever reason, it didn't boot.  So we tear it apart to get the monitor out and replace it with my brothers'; no big deal, I've taken apart laptops before.  Anyway, the remaining parts of the laptop appeared to be in working condition:  two 128MB memory sticks, a DVD drive, a battery (possibly dead),  and a hard drive; the purpose of this post.
So my brother gets the monitor and a single 128MB memory stick (which appears to not be functioning, but that's his problem), and I get the DVD drive, a 128MB memory stick, and the hard drive.  I figured that since the models were exactly the same, I could just swap it into my working laptop and boot the thing.  Well, I was right.  It booted up to an operating system chooser that was labeled Fedora Core, and had the two operating systems DOS and Fedora Core Linux.  I boot up the Fedore Core flawlessly and come to a log in screen.  I do not know any usernames or passwords for this hard drive.  So here is my question, /comp/:  How shall I go about getting logged into that machine?

>>4
For better security you'd have to encrypt everything.