The worst are Trojan horses , programs that claim to be one thing but are really another, such as a program that is supposed to be a calendar but secretly erases your hard drive or copies its contents somewhere else.
The worst are Trojan horses, programs that claim to be one thing but are really another, such as a program that is supposed to be a calendar but secretly erases your documents, pictures, or even your entire hard drive or copies its contents somewhere else.