password protected system

I inherited a Dell Dimension XPS R400. It seems to be a nice computer, but, it is password protected. It is running XP PRO. When you get to the start up screen, it asks for a password. No hints are given and it doesnt say to install a boot cd. Ive tried removing the battery overnight, and changing the jumper for 5 seconds.Is there anyway to get past the password so, I dont have to reinstall. I dont have the installation cd for XP.