[maximumoverload]

Unfortunately, opening and forwarding random PowerPoint presentations is all some of my relatives do on their computers.

[userbinator]

This is even more problematic, as all it takes is for someone to be enticed into opening one which silently installs malware, and then they'll think it's "perfectly fine" and forward it to someone else who trusts them.

[cpncrunch]

Get them to use OpenOffice or LibreOffice instead of MS Office, as most attacks will be directed towards vulnerabilities in MS Office.