The CIH virus with its April 26th payload in 1998 was one of the most destructive virus attacks I witnessed during my career in cyber-security.  3 of our PCs in the burn-in room were being built & did not have AV in place — so they accidentally got infected.   Those 3 PCs would only boot to a basic prompt as the BIOS had to be re-flashed to fix these issues & hard drive had to be re-imaged. 

However, as good news — our company had implemented strong AV protection for ALL users  & as virus had been predicted, we had cleaned many copies off user PCs.   Having seen the damages of this highly destructive malware first-hand was impressionable. 

It helped establish an importance for security software & keeping all software up-to-date.  That example has helped keep me virus-free from that date forth.   

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

https://en.wikipedia.org/wiki/CIH_(computer_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.