Sandy should press the Caps Lock button or the Num Lock button and check the light on the keyboard.
Caps Lock button or the Num Lock button
Step-by-step explanation:
There are many buttons on a keyboard, but in order to verify if the power is connected or not we need to press buttons like caps lock or num lock. These buttons come with a light indicator on them which lights up as soon as they are pressed.
If the keyboard is disconnected, it will not receive power and will not be able to light up the button. Since this method is following by every users to check whether their keyboard is working or not.
Also some computers have special features like In-built light, which turns on by pressing Alt+Space bar.