Unusual problem with Pagemaker 7

I have lost all my PM7 folders - one moment they were there, the next moment gone. I've spent two days seaching for them with no luck - I had a recent backup but have lost important recent files from the missing folders. I do have InDesign but I've had Pagemaker from the beginning and have been very happy to stick with it! Has anyone any ideas about the recovery of these folders and their files - please?