Locked bios screen without suffix.

Good day to all of you. i need help to fix my laptop which is Dell Inspiron 3542 I3.

problem is this i was not around for few months and i keep laptop at home and someone use it dnt know who. but he put a BIOS admin password and now when  i turn on i ask for administrator password and wont bootup. i tried to remove battery but it same. in fact am not original owner of this laptop i bought from a student of university. can anyone tell me how to remove this password?

whenever turn on i got this screen.

my laptop's details are follows

if anyone know solution please email me at my email  which is  .

thanks