Logging Into Hidden Administrator Account?

I need to login into a hidden administrator account on Windows 7. There are a few complications.

1) The built-in administrator account is hidden, and as described below, I cannot elevate my privileges.
2) I created an administrator account, called "Secure," but it's completely invisible! By using an unsupported (and stupid) registry tweak, I have hidden the "Secure" account from view, such that even in UAC prompts, the "Secure" account isn't visible and I am unable to elevate my privileges. This means that I cannot get beyond any UAC prompt.

How can I either login or elevate to the hidden, built-in "Administrator" account or to the "Secure" administrator account that I created and then obscured through an unsupported registry hack? Note that I cannot undo my changes to the registry that obscured the "Secure" account because I can't run regedit with the necessary privileges. Note that due to my unsupported registry hacking, the "Secure" account does not appear on the login screen that displays at startup. I cannot login to the "Secure" account by selecting "Switch User."

I cannot find any way to access a Username/Password login prompt anywhere in Windows 7. I could login to the "Secure" account, if only I could access a username/password login prompt. I know the password for the "Secure" account -- I created it, after all! I cannot run a command prompt with administrator privileges. I even booted into Safe Mode, but that does not give me the option to login to the "Secure" account, either!

To get a prompt that includes a username and password field from within Windows 7 -- even in a Standard (non-Administrator) account follow these steps.
1. While holding down the Shift key, right-click the program you want to run.
2. Select "Run as a different user."
3. Type the username and password of the account.

This will not work for disabled user accounts, like the built-in Administrator account. To use the built-in Administrator account, you first have to enable it. This does work for hidden (but still enabled) user accounts. This will allow you to run a program as though you were a different user.