Try to log on on an another admin account on your Machine and change that.
if there is no other admin you have to create a new user as an admin.
Reboot. When the screen goes black hold "command- s" to enter in Single user mode
type /sbin mount -uw /
type rm /var/db/.AppleSetupDone
The system, will restart with like setting up a new machine (dont worry your user files are not deleted)
set up a new account. then after that check teh user accounts on system prefrences. remove managed and boot on to your pervious user.
After managing to make your Previous usre an admin delete the other extra user that you created
Try to enable firmware password so that you can only do that to your machine. http://support.apple.com/kb/HT1352
Turn on Filevault to protect your files. http://support.apple.com/kb/PH7033
When you first installed OS X, an administrator account was created. Its like deleting the .applesetupdone. The New account that you created should always be the Admin. I dont know what happened there.
Login to the newly created User (that yousaid is anon admin). Open Terminal App
dscl . -append /Groups/admin GroupMembershipRealName "<
Your USER ACCOUNT NAME>
it will ask you for password. Type the password of your newly created account. If it does not work use the password of your previous admin account. If not we are going to reset the "root admin" password for this to work. You will need the Snow Leopard DVD to do that.
Reset the password with the Installer Disk.
Boot from DVD and use the Password Reset program
The newly created user is admin, but it is also under parental control like the old admin account. And no matter which account I use, old or new one, the modification to the other account just doesn't work.
My MacBook Pro package doesn't contain Snow leopard DVD, and I tried to install it from Internet several times, but all failed. It reported at first that the whole process would need more than 9 hours, but later ended with failure.
Is there any method to reset the MacBook to the Initialize state?