Thanks for your frank reply. I know a lot of people are nervous about buying software on Ebay, but I think the worries, while not unfounded, may also be overblown. I've bought quite a few PC games there, and I've never once had any real problem. Virtually all of them were used US-retail items, box and all, perfectly genuine, perfectly legal, and darn cheap. A few of them were actually new-in-box. Only one turned out to be a questionably-legal "not for resale" bundle disc.
The trouble is, people get tired of a game, so they sell it and use the money to buy new ones. Nero, on the other hand, stays useful for a long time. The auctions for Nero all boast that they're "new, never used!" etc, which is making me wonder where it all comes from.
No worries, I wouldn't get into something like that, that would push my fishy-o-meter off the scale. I don't think I've even seen an auction like that, in fact.