An operating system coordinates the activities of computer hardware
It is a destructive virus that rewrites itself and is an executable program with its own code. It usually destroys the program it infects.
Operating system
A program that appears to be legitimate but is designed to have destructive effects, as to data residing in the computer onto which the program was loaded.
The special instructions that control the activities of a computer are called programs. A program is a series of instructions written in a way the computer understands.
device driver
your mom over your shoulder
executable program
That's a 'key-logger' program.
A function instructs the Word program to perform a specific task.
If the program is a virus, it is intended to harm your computer, make your computer a zombi or to gather your personal data from your computer for criminal use.
A virus is a piece of a program that attaches itself to other programs. In contrast, a worm is a full program that spreads itself, and a trojan is a harmful program that passes itself off as, and in some cases might also be, as useful program.