Great story! How were you able to diagnose the issue? I imagine it must have been quite a bit more difficult back then before the advent of Google.
I’m assuming someone somewhere told me about viruses and gave me a copy of McAfee.
I remember when it all clicked though. All our computers started acting the same with the ping pong ball. The virus was spreading whenever I was inserting a floppy in an infected machine. I had a ton of floppies to clean.