How to Unlock a Microsoft Keyboard
Locking the keyboard and computer prevents strangers from using your computer. This is a good idea in a shared household or a dorm where people pass through your space. To unlock your keyboard, all you need is your Microsoft username and password, or the username and password of roommates, relatives or friends who also use the computer.
Press the "CTRL," "ALT" and "DEL" buttons at the same time. This causes a dialog box to open up, which asks you for your username and password to unlock the keyboard.
Review the text in the dialog box, which reads, "Only domain/username can unlock this computer." You should see an icon and username that you chose when setting up your computer. If the username listed is not yours, you will need to get the password from that user.
Enter the appropriate password.
Click "OK" to unlock the keyboard. The dialog box will disappear.
Press "CTRL/ALT/DEL" again to log on to the computer if it does not log on automatically.