Unable to change password.

Thanks again everyone for taking the trouble to give me the benefit of your experience. The laptop donor, by the way, was my daughter's sister who had some help setting it up where she worked; so I was not worried about the programs etc. already installed which were fairly minimal.
I ended up doing what Tookeri suggested. I set up a new user/administrator account in my daughter's name with the password she wanted. I hadn't realised if, or how, this could be done but it seems to work ok. It appeared that I could disable the other administrator but that didn't seem to work so I warned her not to switch user when logging on.
Thanks once again everyone.

omg look boot from the disk, go repair when u get screen look for cmd
use net user to add new user and pass word
use net usergroup to give admin rights reboot
u must add password or will fail
renameing cmd no longer works
not hard to do but find few people even understand the basics
older ways doing this no longer work
this is most current way get around probem