Sorry for not posting what happened. How else do we learn from other's mistakes?
Like I said, it wasn't a pagefile or a hibernation file. When I tried to rename or delete it Windows 7 reported it was in use. I dropped to safe mode copied it to a backup and rebooted. No complaints. It's gone and it looks like my system is running smoothly again. I'm still not sure what it was but I've been playing extensively with a backup program (EaseUS - Don't buy) so I think it was related to that. I'm awaiting the arrival of my replacement SSD so I can get my machine off the dining room table and back to my office.
Thanks for asking,