If your computer is on a domain, you can't create a password hint.
When you create a password to log on to Windows, you can create a hint to help you remember it. If you've already created a password, you'll need to change it to create a password hint.
Open User Accounts by clicking the Start button , clicking Control Panel, clicking User Accounts and Family Safety (or clicking User Accounts, if you are connected to a network domain), and then clicking User Accounts.
Click Change your password.
Type your current password, type the new password you want to use, and then confirm your new password.
Type the password hint you want to use. Remember that anyone using the computer will be able to see the password hint.
Click Change password.