And a bit more from the Data Doctors (great site)
The first instances of this type of attack were discovered in 1998 when the 'CIH' or 'Chernobyl' virus was discovered in Taiwan.
This worm had a trigger date of April 26th, 1999, which reportedly affected more than a million computers in Korea.
Although
this virus is rather old, it is still possible that it is in the wild
and could attack a computer that had outdated or no anti-virus
protection. If the computer in question had anti-virus software that
was at least from the late 90's it should have been protected from this
particular attack. (Norton Anti-Virus had an update for this virus as
far back as June of 1998.)
Variants of the original code have
been discovered as recently as late 2002, but they all use the same
techniques from the original, which means even older anti-virus
protection should guard against it.
A quick way to know if the
CIH virus or one of its variants is the cause of the problem is to scan
the hard drive for viruses in a completely different machine. If it
attacked the computer's BIOS, it will still be on the hard drive and
will likely have infected many files as well.
Another possibility
is that someone attempted to do an upgrade of the system without
realizing what they were doing (we have seen this on more than one
occasion in our shops).
If an intentional upgrade goes bad, it
can render the computer unbootable. In some cases the BIOS can be
're-flashed' or replaced and in others there is little that can be done
to cost effectively resurrect the main board.
The very
possibility that a program can attack computer hardware components is
just another reason for everyone to avoid e-mail file attachments like
the plague!
