how to make appear administrator? help I messed up my registry

my brother is downloading so much stuff and it slowdown our internet, so I use a net limiter program to cut dl speed into half. so I have created admin account so the standard user cannot modify and uninstall the net limiter.
I have now 1 admin and 1 standard user.

I used this registry that I found at google to hide the admin from login screen, and it works like a charm :)

Hide User Accounts in windows Vista and Windows 7
at Run type regedit
Once in regedit go to HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\CurrentVersion\Winlogon

In the left panel, right click on Winlogon and click New and click Key.

Type SpecialAccounts and press Enter

In the left panel, right click on SpecialAccounts and click New and click Key.

Type UserList and press Enter.

In right panel of UserList, right click on a empty area and click New then click DWORD (32bit) Value.

Type in the name of the user account that you want to hide and press Enter.eg: Everyday Account.

In the right panel, right click on the user account name and click Modify.

To hide the user account – Type 0 and click OK. (number zero not the letter)
Whenever you want to use the account just unhide the it by typing 1 instead of zero.

however, my big problem is how can I make appear back the admin account into windows login screen? since standard user cannot modify the boolean 0 and 1 from registry help
I have tried login to safe mode ,but still no admin account showing up T_T

Built-in Administrator Account - Enable or Disable - Windows 7 Forums
Built-in Administrator - Enable from WinRE - Windows 7 Forums

Once you undo what you did from the Built-in Admin account and then disable it, I would password the Admin account on the Log On screen so it can function as you want it to without interference by the other users or needing special hiding tricks. It is your account and your password will see to it no one else accesses it.

A Standard User will be prompted for the Admin password if they try to make changes but do not give in to the tempation to hand it out ever. They can wait until you look at what they are doing to decide if you want to approve it with password. If you have a weak moment and give the password out once, then immediately change it to a strong password.

i already put password to admin account.. but i want to hide it from login screen it just did go wrong and I cant make it appear back i tried the links but i cant make any changes as standard user it always said "access denied" huhu

You should always be able to bring up the hidden Built-in Administrator, even if necessary from the Command Line on your Win7 disk or System Repair Disk as shown in the tutorial linked earlier.

Once you bring it up you can undo whatever you did in the Registry, or create a new Admin account to move everything over and then delete the old one.

At most you should be able to get by with a Repair Install .

However if you really want to start over to obtain and maintain a perfect install then I suggest you follow these same steps to do a Clean Reinstall - Factory OEM Windows 7 which compile everything that works best so that if you stick with only those tools and methods you will have a perfect install for as long as you do. The choice is yours.