Sticky Keys - User can no longer use/enter information from the keyboard
Sticky Keys is an accessibility feature in Windows for people who have difficulty holding down one key and pressing another. Often times this feature is turned on by accident by pressing control, shift, alt, or the windows key 5 times in a row. A pop-up window will usually appear asking users to confirm that they are turning the feature on or off.
If you hit any of the modifier keys (shift, ctrl, alt, or windows key) 5 times in a row it will cause the sticky-keys accessibility function to turn on (sometimes gives you a message, sometimes not) which will make it act like the key is being held down. The key will not unstick until you repeat the sequence of 5, or reboot.
This feature can also be turned on and off via the Accessibility icon in the Windows Control Panel. To turn off sticky keys once enabled, just press "CTRL+ALT+DELETE" at the same time.