We found out that version 0.8.6 of "MobileNoter Sync Client" has problem in the uninstall workflow. You can uninstall the application from the Add/Remove windows snap-in and this works ok, the application is uninstalled from your system. But not completely... shortcut in the windows Startup folder is not removed. And on a next boot up, when this shortcut is called by Windows, MobileNoter asks you if you want to install it.
To avoid this, you have to remove MobileNoter shortcut from the Windows Startup menu (Start->All Programs->Startup).
We understand how annoying this could be and apology for the inconvinience. The problem will be fixed in the next update that will be published soon.