Now there's a game I'd forgotten about!
Try having a look in the registry to see if there is anything on save game locations. Should be in something like hkey local machine/software/monolith productions/no one lives forever.
Hopefully in there will be the save game location, and you never know, you might find a clue there why it's not picking up your saves.
Not wanting to teach you to sick eggs or anything, but are you sure you put the saves in the right place? You've done a save on your new installation and it appears in the same directory as the old ones? How about creating a new save, renaming it, and then rename one of your old saves to the newly created save files name? Worth a crack! Make sure you take a backup of the old ones first obviously!