Ethically, I'd say either go with just delete/format or examine only enough to try to find the original author.
Personally, I'd love to know what happened to some of my old CNet and Image BBS pfiles (doors) I wrote/modded way back when. I gave those disks away back when I first sold my C64 stuff and went to Amiga. It would be interesting if someone came across them in a collection somewhere.
They sold you the machine with the files so its their problem they weren't deleted
That's kind of a bad stance... What if the machine was stolen, years ago? What if it's a drive that was supposed to have been disposed of, but somehow made it's way through the resale chain with no disposal? There's all sorts of ways that data could be left on the drive that AREN'T the original author's "problem".
