There is a concealed account, (global Admin account) which may be what you are seeking.
There are a couple of ways to open this:
1. Open a command prompt(Run as Administrator).
Type the following command and enter.
net user administrator /active
Log out and see if you have a new alternative login, as well as your existing one. If not, do it the long way.
2. Shut down the computer for a cold boot. Tap the "F8" key as you are booting.
Select "Safe Mode with networking" from the boot menu.
Log into windows 7 with your personal account that holds the administrator access.
Open a command window (START--->RUN--->CMD.exe). At the command prompt type the following net user administrator /active
Log out and log back in as administrator.
and another way:
3. Go to Start
Type Control UserPasswords2. (or Open the Start menu, and type lusrmgr.msc )
Click Advanced.
Click Advanced again.
Select Users.
Select Administrator and untick the the box “Administrator is disabled”
Now log out and login as Administrator.
The action leaves you a little more vulnerable to outside attack. Not a big issue if you are confident with your anti virus control etc. But it may be a good idea, if you are not totally familiar with security risks, to return to your normal user account afterwards. Fwiw. I have used three ciomputers in my own home, totally on the Global Admin account, since the early Vista Beta days. I have not exerienced any out of the ordinary virus or trojan problems