Change Vista start menu power button - not working

[Craig321]

I just tried to change the start menu power button to shut down rather than sleep through the power plan.

When I try select shutdown rather than sleep from the menu I get this:

UAC is currently off so I'm definitely a full administrator.

Any ideas?

 

[Craig321]

turning uac off doesn't necessarily mean you're an admin. You could still have a limited account

I can confirm I'm using an administrator account

Not a domain machine is it by any chance?

Nope

 

[Craig321]

I've never tried to change this option, so I'm unsure if it's ever worked.

Vista Ultimate x64 SP1 here.