UserName/Password HELP!

I bought a refurbished Dell Laptop. When I turned it on the first few times it showed me a Windows XP log on window with the username for the previous owner "Dave." I used to be able to just press "Enter" and log into Windows.

Now it won't let me. It says it requires a password. If I just treat this as I don't remember my password how would I go about retrieving it or changing it on the initial log in screen???

Help I can't get into my computer!!!!!!!!

Or if anyone knows how to overide the Username/Password screen that would be appreciated also! ANYTHING SO THAT I CAN USE MY COMPUTER AGAIN!!!


Thanks