There are some password recovery cracking software out there. Do some google searches, may-be you can find one that will work for you. (I'm talking about the legit kind, just made for this issue).
You could also format and reinstall and operating system. Access BIOS, change first boot from HDD to CD. Insert windows OS install and restart. This will start the windows install process. Format HDD and reinstall windows. This is probably the best option seeing as you have no idea what's on that laptop. "Viruses, Adware, Spyware...ETC" You might as well start off clean...
Good Luck!