laptop won't log on

I have a pavilian laptop which I hadn't used for some time. It used to work
When I log on it goes to the xp screen and then cycles to the safe mode (etc) buttons.. back and forth.
I've forgotten whats on the computer but would like to be able to access what ever is on there.
I bought the laptop from craigslist so I don't have the soft ware. My home pc is down right now so I have to access from the lbrary