Well, it's been a while since I played SE5, and I was just going to install it on my laptop ... for old times sake. And I discovered ... I never saved the CD Key number, and the game needs it to install.
I am soooo stupid.
I'm guessing, an older patch removed the need for a key, which is why I didn't keep it, or do I remember wrong? Anyway, I suppose I should ask Strategy First if they'll sell me another key, for a nominal fee ... but I'm probably not going to take it that far.
So if anyone has other, legal, and moral options, I'd like to hear about them. Otherwise, I can be pretty satisfied with SE4.
Cheers all.