Helping people with computers... one answer at a time.
Without the "archive messages" selected, there is NO way to retrieve MSN Messenger History.
Are you *sure* there's no way to retrieve MSN Messenger history without "archive messages" selected?
I've actually been asked "are you sure?" several times. I'm not sure if it's suspicious spouses or parents - or perhaps nervous spouses or kids - but here's one example:
From your article Can I retrieve old MSN Messenger conversations? I just wanted to quickly ask if there is any other way to retrieve MSN history if the "auto archive messages" option is not chosen. There must be a way!!
Not that I'm aware of, anyway. Conversations, when not being archived, may never even hit the disk, so there's nothing saved to be recovered. There might be small, tiny chances that some memory swapping happened and that a fragment landed on disk, but again the chances are small and it was probably immediately overwritten. The same tiny chance applies for any equipment that the conversation traveled through.
To go further down that path you're really talking computer forensics - the stuff of computer detectives pulling apart hard drives to see what can be recovered even from deleted data. But as I said, it's unlikely there's anything TO recover. And that's an expensive path to go down.
If you're looking at all this before the fact, you could install various forms of spyware. My prior article How can I keep my kids safe from internet garbage? discusses this, and has links to some resources.