Adobe Digital Editions won't stop trying to install itself

I used to run ADE 4.0.3 on Windows 7.  After I uninstalled it and every time I rebooted my PC, a setup window pops up asking me to install Adobe Digital Editions 4.0.3.  This annoying setup window was one of the reasons why I uninstalled ADE.

I checked under System Configuration and Task Scheduler, and can confirm that setup is not being called by any automated settings.  Upon checking with Sysinternals Process Explorer, here is the information I found:

And no, messing around with DropboxUpdate.exe (which is a 131kb file) did absolutely nothing.

Question: How do I make this stop once and for all? 

P.S. the blue bar basically censors out my Windows username.