Final answer:
Computer viruses must be executed to inflict damage on a digital device, requiring either automatic execution within another program or inadvertent user activation.
Step-by-step explanation:
Typically, computer viruses must be executed to attack and do damage to a digital device. Simply downloading or installing a virus does not necessarily mean it will activate. Viruses often need to be run, or executed, to perform their malicious actions. Execution can sometimes happen automatically if the virus is part of another program that gets run, or it could require a user to inadvertently activate the virus by running an infected application or opening an infected document.