Windows 7: Onenote 2010 lost file association

My onenote 2010 went haywire. It no longer sees existing .one pages.
If I find the .one file on the drive in explorer and open them they open just fine. But they are no longer attached to the sections.

The sections are still there in the left hand pane but are empty. If I right click and open the notebook withe the "open Notebook .onetoc" file nothing happens.

It is as if the toc files have been cleared out.

Any advice?

I found all of the .one files on the drive but don't know how to load them back into the desired sections in OneNote.

Win 7 x64 Office 2010 32bit

Thanx in advance
Ted