Hi Jacqy Ley,
Thanks for writing in our forums!
The problem you ran into seems to be caused by the Notifier trying to add automatically a monitor for each MySQL service you installed, to do that the Notifier relies on the .INI configuration file (in the same way the Windows Service relies on the configuration file in order to start) to detect some parameters needed to add the Windows Service for monitoring purposes.
Since the excerpt of the Stack Trace you copied into your post indicates the Notifier tried to automatically add the default MySQL Windows Services, tried to inspect the INI files and failed, I suspect that you somehow erased those INI files. Can you please verify this?
I recommend you close the Notifier, uninstall it (via the MySQL Installer or via the Uninstall a Program option in Windows), and then uninstall the MySQL Server(s) you installed, make sure you remove all leftovers of the installation in C:\ProgramData\MySQL and reinstall again using the MySQL Installer, you should not run into any issues.
Also to make our product better, please raise a bug report in
http://bugs.mysql.com for the Notifier product stating the Notifier does not start and throws an unhandled exception when the INI files are not found (if you verified this was indeed the root cause of the problem).
Best Regards.
====================================
Javier Treviño
MySQL on Windows Team