The problem may, of course, have nothing to do with either application, but perhaps with another app that periodically clears the clipboard. I'd suggest checking what 3rd-party apps are running in each app and also what background processes are running in Windows.
Regarding the Word version details, see File>Help>About.
As for disabling OneNote, see, for example:
http://www.ehow.com/how_6826398_disa...t-onenote.html