Windows 7 Lost Administrator Account Access on Windows 7 After Creating Limited User

Try this:
Right-click on command prompt and choose 'run as administrator'.
Then type:

net user administrator /active:yes

then press enter. You should see a message stating that the command completed successfully. Type exit and press Enter again to close the Command Prompt window.

When you restart Windows, you'll see a new account labeled simply "Administrator." The first time you log into this account, Windows will tell you that it's preparing the desktop before the system's default desktop appears. Click Start > Control Panel > User Accounts and Family Controls > Change your Windows password > Create a password for your account, enter your password twice, add a hint (if you wish), and click Create password. (If you use Control Panel's classic view, the settings to create a password are in the User Accounts applet.)

To disable this administrator account, follow the steps above to return to the Command Prompt in administrator mode, type net user administrator /active:no, press Enter, type exit, and press Enter again.

This should work as it's the same fix for vista but if not, post back..