Windows Vista Biz: How To Enable Administrator Account

To change user to Administrator, here is how to do it:
You will need to change the security policy.

1. Navigate to: Control Panel >Administrative Tools >
Local Security >Local Policies>Security Options>
Accounts: Administrator Account Status
2.Right click on Accounts: Administrator Account
Status and select Properties.
The Properties window will be launched.
3.Select ‘Enabled’>Apply the settings and click ‘OK’.

Doing this will allow you to login as the Administrator.
Although, adding yourself to the Administrators group should
have the same effect as logging in as Administrator. But
that is not always the case with Windows Vista