Can't put updates into computer I have no authenticity code

can't put new update version into my computer as I don't have the Authenticity and / or the administrator access. This computer was a donation from a company that takes old computer and fixes them and then donates them to people with a disability and on fixed incomes and I haven't been able to contact them about this problem. This is the product that they originally put into this hard drive and I wanted to continue. Also the day that ubuntu said I was supported anymore as account had fan out was the same day my computers volume stopped working., is that just a coincidence ? HELP thank you for your consideration , Deana Steele
   <email address hidden> hm. ph. 778 - 422 - 1587