Cell Phone Unlock Code Needed?

I found a Samsung Blackjack phone and the phone itself is locked and I can't access the phone and try to find out who it belongs to. I went to the store and they told me they can't retrieve the info because the phone was reset because the person reported it lost and was likely sent out a new replacement phone.

So now I have this phone and I was wondering how can I unlock the unit so I can use the applications on the phone like the alarm clock.