Visit the Local Security policy (MMC).
Firstly click on Vista’s Start orb, then in the Start Search dialog box type:
secpol.msc
You must include the .msc extension.
Drill down to Local Policy, Security Options
Double click Accounts: Administrator account status, and select enable.

Security settings > Local Policies > Accounts: Administrator account status > enable it.

Logon to Vista using your usual account.
Launch the cmd prompt – Make sure you select, ‘Run as administrator’
Net user administrator p£ssw0rD
Net user administrator /active:yes
Switch User, or logoff
Logon as Administrator Password p£ssw0rD
(Your password may be different!)

Detailed Instructions to activate the Administrator

Logon to Vista using your normal username and password.
Click on the Start button
Click on Start Search.
Type, cmd.
Right-click cmd, select ‘Run as administrator’ from the shortcut menu.
In the black ‘DOS box’, type the following at the command line:
Net help user
The idea of the last command is just to observe the options for Net User. In particular, examine the syntax to set the password.
The next instruction is the crucial command. I have chosen password = p£ssworD, you may want to choose different characters.
Net user administrator p£ssw0rd
Net user administrator /active:yes
Check the message : The command completed successfully
Switch User, or logoff
Logon as Administrator Password p£ssw0rD (Your password may be different!)

Attempted to run command but was told by the machine that I do not have permission to enable or disable (funny how I was able to disable just fine…) hibernation.

…how I hate Vista, let me count the ways.