How can virus affect us?

Computer viruses affect the health of your computer, just like their biological counterparts make you sick. Typical payloads of computer virus include annoyances (e.g. affecting your mouse / keyboard), removing files from your hard disk and formatting your hard disk. It is only with the discovery of CIH virus that corruption to the BIOS has been added to the list of payloads.
Computer viruses may seem remote from you. This may have been true in the old days, when few of us had a PC at home and viruses were spread slowly with the exchange of floppy disks. However, times have changed; viruses can now reach us through a number of routes. They may arrive in shared files in the server, in emails from your colleagues, or in files downloaded from the Internet and BBS. Worst still, some vendors have delivered machines or CD-ROMS with viruses pre-installed. So, your files and data are at stake.