The other discussion is getting too long. But you've narrowed the notifications are coming from just 2 applications.
1. Nero. My bet here is that it's InCD and Imapi. Try it without.
2. Camtasia. My bet here is that while it's active the disk could be written to, the disk space change and that triggers Explorer to refresh it's view.
The Camtasia issue is actually evident in other applications. Said application authors learned years ago to make a file as big as they need and then write into that file. If the file is opened and written via the standard way, Explorer will flicker. And this is not a bug.
Cameras that make great holiday gifts
Let them start the new year with a step up in photo and video quality from a phone.