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**  Special Information about Unique Computer Viruses TECHNOTE.TXT  **
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**  Symantec AntiVirus Research Center (SARC)    September 2, 1997  **
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 * Adding Program File extensions to Detect/Repair Excel Viruses
 * Norton AntiVirus Program Upgrades
 * Disappearing Hard Drives
 * Additional Information


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** Norton AntiVirus Program Upgrades                                **
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If your version of Norton AntiVirus (NAV.EXE, NAVW.EXE or NAVW32.EXE)
is dated before June 1, 1996, you should update it with the latest
program updates available. As viruses continue to be discovered with
alarming regularity, the NAV virus definitions files have grown in
size to counter the latest threats. Applying the patches will ensure
that your installation will continue to accept the latest (and
largest) virus definitions files. Using older versions of Norton
AntiVirus can cause false detections when the new virus definitions
are installed.


Norton AntiVirus 3.10 Engine Update (UPDATEME.EXE)
--------------------------------------------------
To upgrade your Norton AntiVirus 3.0 program:

  * Download the file called UPDATEME.EXE
  * Place the file in an empty directory and execute the file
    to extract its components.
  * Enter:  PATH;  at the DOS prompt.
    Don’t forget the semicolon. This command temporarily disables
    your path statement and will prevent corruption of NAV Network
    Manager installations.
  * Run UPDATE.EXE to create a set of install files.
    To place these files on floppies and create a new installation
    disk set, enter A:\ when it prompts for a location to EXTRACT the
    files to.
  * From DOS, run INSTALL.EXE.

  * After applying this patch, you must also update your virus
    definition set.


NAV for Windows 95 v1.0, 95.0b Large Volume Update (NAV95OB.EXE)
----------------------------------------------------------------
This latest patch also adds support for Microsoft Service Pack 2 (FAT
32/large volumes) and will be required to apply the September 1997
virus definitions set.

To upgrade your Norton AntiVirus for Windows 95 program:

  * Download the file called NAV95OB.EXE
  * Place the file in an empty folder and execute the file
    to begin the installation process.

  * After applying this patch, you must also update your virus
    definition set.


If you need additional instructions, a FaxBack service is available
at (541) 984-2490.  Request documents 4200 and 4221.

UPDATEME.EXE and NAV95OB.EXE are located where the monthly virus
definitions files update are normally found. They are available for
download from the Symantec BBS, the Symantec FTP or Web site,
CompuServe, America Online, or Microsoft Network. You can also call
Customer Service at (800) 441-7234 to order a disk set.


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**  Disappearing Hard Drives                                        **
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Several viruses, such as Frankenstein and Stoned.Empire.Monkey, cause
your hard disk to "disappear" when booting from a clean floppy disk.
This occurs because the virus either encrypts or relocates the hard
disk partition table (a vital part of the disk's system area).

All "appears" well when you boot from your hard disk because the
virus actives in memory and tells DOS where the partition table is
relocated, or acts as the partition table itself. If you boot clean,
DOS can't find the partition table and the virus isn't around to give
directions. You may receive an "Invalid drive specification" or
similar error when trying to access the hard disk.

When you boot clean so NAV can repair such an infection, the hard
disk will not appear in the drive list. Don't worry! NAV, with the
default options enabled, will bypass DOS and look directly at the
hard disk to check the system area for infection, no matter what you
scan. For example, scanning a floppy disk will scan memory, the
floppy disk, and the system area of the hard disk. If such an
infection is discovered, you are alerted appropriately.

NOTE: IDE hard drives larger than 1024 cylinders often require the
use of additional driver or overlay files. If you have such a drive,
you may need to include these additional files on your Norton
AntiVirus Rescue Disk to ensure recovery from virus emergencies. Make
sure that any special driver or overlay files for your hard drive,
which are part of your normal system configuration, are included on
your rescue disk.


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**  Additional Information                                          **
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Additional information regarding this virus definitions update can be
found in UPDATE.TXT and WHATSNEW.TXT.