how to access password to allow ubutnu updates

Okay peeps

Your dealing with a person who is not literate when it comes to understanding a computer as I did not install UBUNTU

So I need to know in very simple terms how to reset the Ubuntu password as every-time new updates come through I cannot complete the task.

I am not computer savy so appreciate your help in this matter as there must be a way to go to files and search, thanks to those who have already tried to help me but I should have been more informative, I suck at computers (-:

Bashing Om,
  sorry I followed your instructions but would not accept the command mount -0 rw, remount/

It did come up with a name, however I had to shut down as screen populated with different commands I keyed in and therefore I could not return to the top as no backspace function so had to shut down . What am I doing wrong please.