How to get around the admin password?

I was in the middle of re-installing windows, when the pc I was working on crashed.  It was a thermal event issue.  I took the hard drive from that pc and moved it to another.  When I did that, I was able to finish re-installing windows.  Now that I've completed that, it is asking me for an admin password to sign on to the pc.  When I originally setup the pc, I never put in an administrator password.  I've tried all of our system passwords, just hitting enter and just about every other password I can think of.  Is there anyway of getting around it?  I really need to get the files off of this pc and on to the new one I have.  Thanks!