M1710 xps can't log in

I have dusted off my xps m1710 for the first time in, well a long time. 

My problem is I have no idea what the password is, I have tried various passwords I've that I was certain was the correct one but can't get anywhere.

And yes you have guessed it, I can't find any of the discs that would help me at least take it back to factory settings.

There is unlikely to be anything on the laptop that I need to keep so any advice or help will be appreciated.