I figured out what 'ClientShell.exe' is. It's Wireless Sync. Since I moved my STARTUP application to another folder to prevent it from running, I haven't been getting those repeated notifications. However after installing ActiveSync 3.8, the little icon appeared on my screen again today. Low and behold... after a couple resets, I had several notifications again!

I think we found one of the bugs. Wireless Sync 5.5!