I found the answer--
After installing the MySQL ODBC drivers on a Windows platform, no listing appears for the drivers under the Drivers tab of the Microsoft ODBC Data Source Administrator.
Try using Regedit to view the registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\ODBC Drivers
Select and delete the (DEFAULT) string, then restart the computer.
WARNING - WARNING - WARNING: Editing your Registry incorrectly can cause serious, system wide problems that may require you to reinstall your operating system to correct. It is advised that you back up your registry before modifying it.