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Removable Media

Although floppy disks are rapidly becoming obsolete, they are still a major source of virus infections, largely because they are still frequently used to transfer files between PCs and because they are the only way that boot sector viruses can be transmitted.

Every floppy disk has a boot sector and most systems will try to boot them, so every time you put a floppy disk in your PC, you have the potential to introduce any boot sector viruses on it to your hard disk's boot sector.

There are a number of precautions you can take to prevent your PC from being infected by a floppy disk:

  • Scan floppies with an anti-virus program as soon as you put them in your PC. Some organisations use a dedicated standalone PC for scanning floppies - this ensures that any viruses detected have no opportunity to infect networked machines.
  • Remove floppies from the PC before rebooting.
  • Disable floppy booting: this can be done via the BIOS settings. The hard disk should be configured as the main boot device. The floppy disk can always be reconfigured as a boot device if this becomes necessary.
  • Enable BIOS virus protection: many BIOSes offer this function which can detect unauthorised writes to the boot sector. This can cause problems when some legitimate functions, eg: installing an operating system, try to write to the boot sector.
  • Use a Boot Password: you can set a boot password if your BIOS supports it. The system will ask for a password before it boots. Apart from the obvious security benefits, this will remind you to remove any floppy disks.

Remember that other removable media such as USB drives, CD-ROMs and Zip disks can also transfer infected files from one machine to another.

Next: Networks and Internet