What Viruses Infect

Viruses can infect a number of different portions of the computer's operating and file system. These include:

• System Sector Viruses
  These infect control information on the disk itself.
• File Viruses
  These infect program (COM and EXE) files.
• Macro Viruses
  These infect files you might think of as data files. But, because they contain macro programs they can be infected.
• Companion Viruses
  A special type that adds files that run first to your disk.
• Cluster Viruses
  A special type that infects through the disk directory.
• Batch File Viruses
  These use text batch files to infect.
• Source Code Viruses
  These add code to actual program source code.
• Visual Basic Worms
  These worms use the Visual Basic language to control the computer and perform tasks.