Question : power user to reset Admin password

I have a pc which I do not have physical acces to and the Admin account no one seams to know the password
I can log in with a Power User account and can get Regedit to run
is there a way I can change this password from the regestry?
I have tried all kind of methods to change the password
in command line net user usr and pass and I get access denied
I tried to use the command at to schedule compmgmt.msc and same thing access denied
tried MMC in giving user logged in Admin right and it goes fine all the way to apply and then says access denied
I need a solution that work

Answer : power user to reset Admin password

some utilities do change the passwords or reset them... one of them is at the link below.
http://www.petri.co.il/forgot_administrator_password.htm#1
take a look at...