My Guest account has been upgraded to an administrator account, change is not coming back

I am a vista system, a blind fiddle with the computer to enhance the guest account for the Administrator account, not to come back.How do we approach it again?
If the change does not come back, there is a remedy Right?

Afghanistan have to My Computer, right-click, management, and user groups, which can delete it and ban , To look at their own! Guest users will not be changed! Control Panel – Administrative Tools – Computer Management – Local Users and Groups – Users

In addition to the original (Administrator) should not be deleted, other The deleted, we can resume the

guests should not be deleted (Guest) / html/system/winxp/1001.shtml