On Vista Home 32bits: service logon as administrator account fails

I have an application that is installed and runs as a service. Up to Windows XP, the service runs correctly. On Vista Ultimate, the service runs correctly only if it logs on using an administrator account (I open services.msc, go to the service's properties, choose an admin account (instead of "local") and enter the admin account and password. When I click on "Apply" the system pops up a box saying the admin account has received the "logon as a service privilege". So all is good. I then restart the service, and it works fine.

On Vista Home versions, I can do all of this (down to getting the popup box saying the account has received the logon as a service privilege) but RESTARTING the service FAILS! A box is popped up saying "Error 1069 The service did not start due to a logon failure".

Strange that this should happen while I'm carrying out all these changes under an administrator account

I get the feeling that the solution should be very obvious, but somehow, to me it isn't! I have no idea what to do!! If someone knows how to handle this problem, please advise me. Thank you in advance.

For info if needed (please ask if you need any further details):
- UAC is disabled (at least while these changes are being performed)
- The service starts correctly using "local system", but is then unable to access the files and folders needed that it needs to access. These files and folders can vary from system to system. So I can't use that.

I have found the solution. It seems I was not looking in the right place
The administrator account I was using did not have the password correctly defined (in fact most Vista Home users would not have a password set even for the base "Administrator" account, which is usually invisible). I went to: "Control Panel > User Accounts and Family Safety", and set a (new) password for my (administrator) account. After that, under this account, the service started up as normal. Yay!