Vista - Creating a User Account Password

I was helping a friend set up Vista on his new computer and I thought it
would be a trivial thing to create a password for the only existing account
"OWNER-adminstrator" but Windows would not allow me to do it.

I went to CONTROL PANEL - USER ACCOUNTS - CREATE A PASSWORD FOR YOUR ACCOUNT
and no matter what I entered an error message returned "WINDOWS CANNOT CHANGE
PASSWORD"

(I don't believe there is any password currently assigned except "")

Strangely when I went to Windows Help, it mentioned that under CONTROL PANEL
- USER ACCOUNTS there should be a link called CHANGE YOUR PASSWORD which I
did not find???

I thought I would try to assign a password to OWNER another way and hit
CTRL-ALT-DELETE which has a "change password" listing. That entry calls for
OLD PASSWORD & NEW PASSWORD. Whatever I typed in that pop-up also gave an
error message "ACCESS DENIED"

I really don't understand. If there is only one account on the computer and
it is administrative mode, why are these errors coming up?

In this tutorial, it will show you how to reset an account password. Here's the link: Reset User Account Password

I hope this helps.