What are the types of malware?

Some categories of malware are:

    Virus - Software that can replicate itself and spread to other computers or are programmed to damage a computer by deleting files, reformatting the hard disk, or using up computer memory.
    Adware - Software that is financially supported (or financially supports another program) by displaying ads when you're connected to the Internet.
    Spyware - Software that surreptitiously gathers information and transmits it to interested parties. Types of information that is gathered includes the Websites visited, browser and system information, and your computer IP address.
    Browser hijacking software - Advertising software that modifies your browser settings (e.g., default home page, search bars, toolbars), creates desktop shortcuts, and displays intermittent advertising pop-ups. Once a browser is hijacked, the software may also redirect links to other sites that advertise, or sites that collect Web usage information.