Re-Installing on Toughbook

Panasonic CF-18. Belonged to a friend who loaned it to an ex while she wasn't an ex. Luckily, it's usable as is, but... Software is so out of date it's scary, and can't update **** unless you know the pw. Neither he nor I know the pw. I'm trying to reinstall over it with the newest Ubuntu to get rid of the profile and start out new, but it's not seeming to allow me to load/install from my passport with Ubuntu on it. I've never had this issue with any of my comps ruing Linux, but I've never used a toughbook before either. I thought I got it to load using the BIOS, but it loaded right back to the hard dive loading with her profile. Any feedback or suggestions would be more than welcome.