Used Laptop Big problems

[HDDELUXE]

Hi I have bought a used Toshiba Z930 laptop but I cant do much with it beause it has this Supervisor Passwors . I did a lot of reading on my phone and not a tech person I got into the BIOS and see it has Supervisor Password. No worries I call the guy I bought it from but he never answers phone of texts so cant find out from him what that password is. Any ideas what I can do about getting this Supervisor Password ?

I looked when the machine starts and its a TOSHIBA V6.80 BIOS but also boot agent ge v1 3.81 if any of that helps. The only reason I want to free the BIOS is so I can change stuff that I cant do like booting from my portable HD and also to install programs because I cant do that now.

Thanks