Pine Man whoever that "expert" was didn't know his virus from his malware, they are both basically the same and the two words mean the same thing.
The word malware (malicious software) describes any piece of code designed to infect your computer (or mobile device) and make it do things that you don't want it to do, such as mass-mail spam or steal your banking passwords. Trojans, worms, and rootkits are all types of malware.
And so is a virus, in its most technically-correct meaning. A virus is malicious code that spreads by infecting existing files, similar to the way a biological virus spreads by infecting living cells.
A virus doesn't have to destroy your PC, that is self defeating in this day and age.