Windows – Is there any way to enable Administrator account from an limited user account in Windows 7

You can wait for the account lockout to expire. This depends on your GPO but these should be the defaults. The default settings are:

• Account Lockout Duration = 30 minutes
• Account lockout threshold = 5 invalid log on attempts
• Reset account lockout countdown after = 30 minutes

Alternatively, you could reset the password if you have to, if you have the legal right to do so.

You can also enable the admin account from the offline NT password and registry editor, which is mentioned in the post linked above about resetting passwords.

To re-enable a disabled account, right click on "My Computer" on the desktop or start menu and choose manage. Under "Local Users and groups" click "Users". Inside "Users" you will see the Administrator account. Double click to bring up properties and un-check the "account is disabled" and close the properties panel. Then right click the administrator user to set the password of your choice.

You may also want to look into creating a password recovery disk. See here

Go to C:\Windows\System32\Tasks find the related task and assign "read and execute" rights to the user you want to be able to access it. Be sure to assign to "current object only." Then the task will be visible and runnable from the limited user, and it will work if you saved your credentials in it and checked "run whether user is logged on or not."