OK. The registry key had the following files in addtion to reboot.txt:
psa3.tmp
psapi.dll
However, before I had a chance to start looking down that path, I update the video driver. I didn't use a brand new driver, but a driver from the 45.xx series of nvidia drivers, since the card is a GF2 I didn't need the latest driver. No change.
I then got notification that there was a new version of AVAST available, so I ran that update. It didn't seem to change anything, so I updated the audio driver from Windows Update, for the via integrated sound.
The error is gone now, and there is no registry key for PendingFileRenameOperations. I don't know if it was the AVAST update, or the audio driver that fixed it, but I suspect it was the driver.
