Strange possible virus occurance

I received an email with an attached file but no text message today from a fellow who visited a woodworking forum I frequently visit for the first time yesterday. I emailed back figuring it was a potential customer sending me a drawing of some sort to review. I let him know I do not open unexplained attachments.

This fellow emailed back that he had never emailed
me. He did, however, have the mentioned file (it was a personally named file with an unusual name so it clearly was from his computer) on his computer....someone had emailed it to him. He didn't, HOWEVER, have my email address in his address book....he'd never been in contact with me bofore this. The only connection was our both visiting the same forum site.

This is about the wierdest thing I've seen in a reported virus situation. Anyone else have a similar experience.

BH Davis