You will need
  • Keyboard
  • Computer mouse
  • Boot disk
To recover the password for account with user rights on Windows operating system.
XP Home
Restart the computer and press F8 until the Windows startup.

Select the safe mode option and press Enter.

Instead of a user name, write "Administrator" or "administrator". By default this account is not password protected, so no numbers or letters in the field "Password" you need not, just click "OK".

A message will appear stating that Windows is in Safe mode. Agree with this.

Now, go to the "start" button, select "control Panel", and in it the "user accounts".
Choose the account password which you have lost. A dialog box will appear which will offer you, in particular, and to change the password. Take advantage of this opportunity and don't forget to write down somewhere the new password.
Select the "Change password" and restart the computer.
XP Professional and Vista

Turn on the computer and log on under the name of "administrator" or "Administrator". When you see a standard greeting of Windows, press the keyboard buttons Ctrl, Alt and Del.
Select the "Change password" and locate the desired user name. Enter the new password twice to confirm this action , click "OK". Reboot and log in under your name and new password.
Password recovery by accounts with administrative rights.
If your computer have a another account with limited access, log in through them.
Select the "start" button and launch Run.

In the Open box, type control userpasswords2 and press "Enter" on the keyboard or OK on the computer screen.
The window "user Accounts". You need the tab "Users".
Select from the list the user name, password, which is lost and click the "Change password".
Mac OS
Locate and insert into DVD ROM of your computer the disk Mac OS X.
Restart the computer when you see the grey startup screen, press and hold "C".
Select language.
Open the menu at the top of the screen and select "Reset password".
Select the icon for your host hard disk in the pop-up window.
Open the dropdown and select the name of the user account which you forgot password.

Enter a new password and enter it twice in the appropriate fields. Click "Save" and restart the computer.