There are two approaches to resolving missing folders/photos:
1. Change catalog to match current location.
2. Copy/move files from current location to match catalog.
If you want #1, then you must know where the photos are, because you have to choose the current location - dunno any way around that.
If you want #2, then you have to use a plugin called 'Relocation Services' (free, written by me) - you can then point to a root folder where the photos are known to be, somewhere, and the plugin will find them, and copy/move them back where they (supposedly) belong - be prepared to resolve ambiguity if filenames are not unique, and if filenames have changed, you'll need to take some other steps..
robcole.com - LrRelocationServices
Rob