I want to reformat the c drive, but it keeps asking me for the administrator password and I don't know what it is.

Which program were you trying to update? Are you trying to download and install new software (that is not from Apple App Store?) Are you running Mountain Lion (OSX 10.8)? The password needed is your administrator password.

Wait at least a half hour before trying again. That is a common lock out period, though not used in home situations. Ask if someone changed it. The options are not good.


Lost Windows password:

• 
  
• Login as Administrator. Try with no password (load safe mode if you don't see Administrator). Press F8 during boot to access Safe Mode.
  
• Login as other user (if other user is available) and manage users. Must be an administrator.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html
  

Lost Windows password:

• Login as Administrator. Try with no password (load safe mode if you don't see Administrator). Press F8 during boot to access Safe Mode.
  
• Login as other user (if other user is available) and manage users. Must be an administrator.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html
  

You need to get the password!

Get them to unlock / give you the password. This can be more serious than expected.

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Lost Windows password:

• Login as Administrator. Try with no password (load safe mode if you don't see Administrator). Press F8 during boot to access Safe Mode.
  
• Login as other user (if other user is availible) and manage users. Must be an administrator.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html

Lost Windows password:

• Login as Administrator. Try with no password (load safe mode if you don't see Administrator). Press F8 during boot to access Safe Mode.
  
• Login as other user (if other user is availible) and manage users. Must be an administrator.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html
  

Try logging in without a password (hit enter). It just may be the screen saver locking it.
Ask if anybody (that has access to system) if they set a password.------------------------------------------------------------------------------------------------


Lost Windows password:

• Log in as Administrator (try safe mode if you don't see Administrator). Again no password.
  
• Login as other user (if other user is availible) and manage users. Must be an administrator.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html
  

Better if you get that password back.


Lost Windows password:

• Log in as Administrator (try safe mode if you don't see Administrator).
  
• Login as other user (if other user is availible) and manage users.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html
  

Lost Windows password:

• Log in as Administrator (try safe mode if you don't see Administrator).
  
• Login as other user (if other user is availible) and manage users.
  
• Reformat computer.
  
• Use 3rd party software to remove password. Like http://www.top-password.com/reset-windows-password.html
  

There are two options you have. You can either acquire an OS (Operating System) disc to reformat the drive and reinstall the OS or you can return it to first user using the Single User boot mode.
The first option is easiest and erases their data so you don't have to worry about it being there.
The second option requires knowing some basic terminal commands.Final note: Have you tried just pressing enter on the login screen? Many times people don't have passwords but it will still ask for them.

Hi, man. Don’t worry, there are many people forget their admin password or lost it, and there is a popular solution for those who have been locked out by computer. For this solution, what you need is a second computer that can connect to Internet and then freely download Windows Password Recovery 6.0 at http://www.recoverlostpassword.com/products/windowspasswordrecoery.html With it, you can create a reset CD which can be used to reset Windows admin password without erasing anything.