This was one of most destructive attacks of its time, as disabled PCs for unprotected users.  While we did an excellent job in prior company of stopping viruses and had protection in place for around 90% of users.  However, there were still a few unprotected PCs in our large company.  I do recall 3 systems where BIOS was destroyed & hard drive no longer worked — booting up to PC Basic back in WIN95 and WIN98 days.

https://en.wikipedia.org/wiki/CIH_(computer_virus)

20 years ago today! What we can learn from the CIH virus…

CIH, also known as Chernobyl or Spacefiller, is a Microsoft Windows 9x computer virus which first emerged in 1998. Its payload is highly destructive to vulnerable systems, overwriting critical information on infected system drives, and in some cases destroying the system BIOS.