What are the different types of virus?

Boot sector viruses append themselves to floppy disks. If you leave an infected disk in your floppy drive when you turn your system on or reboot it, the virus copies itself onto the boot sector of your hard drive. You cannot get this virus from sharing files or by executing a program – only from an infected disk.

Program sector viruses fasten themselves to other programs. Most will piggyback on EXE or COM files, but they can infect any file that your computer runs when it launches a program.

Macro viruses affect the template used to create documents or spreadsheets, thereby infecting every document or spreadsheet opened with the program.

Email viruses can infect your computer before you even open an email. For example, a virus named ‘Bubble Boy’, which targets Outlook and Outlook Express, can be launched even if it only opens up in the preview window. Just highlighting the subject line in the preview window activates the code. It starts sending messages to everyone in your address book in an attempt to overload and crash the email server.