Hi Evan,
you wrote in /FIDO/VIRUS_INFO at 22 Jul 97:
ET> FPROT from dos.  Remember to use a clean boot disk incase it's
ET> polymorphic.
You a have shuffled names a bit around?
So first the names for differrent types (note that one virus can fit to  
multiply of them):
polymorphic - the virus does look diferrent with different infections
resident    - the virus stays in memory monitoring system calls or
              hardware interrupts
stealth     - the virus tries to hide the modifations he did on his victim
              (these ones have to be resident)
retro       - the virus does attack active or passiv one or more AV-
              -programs
and more...
So polymorphic viruses are not the main reason why to boot from a clean  
disk. Beside it is recommended for all kind of virus - one normally do not  
know the type before scanning -. Major problems that may appear when not  
booting from a clean disk:
- a resident virus might infect all 'objects' that are scanned
- a stealth virus might be able to hide its presence
- a retro virus could be aimed on the special anti-virus program you are  
using
Last but not least I don't let unmentioned that it sometimes could be  
needed to boot from a not clean disks. This could be when using a overlay  
for bigger IDE-drives or when a stealth virus infecting the boot areas  
have encrypted them.
Michael
--- CrossPoint v3.11
---------------