What steps do I need to take to completely uninstall MySQL?

Found a solution on Server Fault: How can I reset the password for MySQL?

Using Windows 7, here's what I had to do:

• Uninstall MySQL using the uninstaller
• Delete C:\Program Files\MySQL
• Delete C:\Program Files (x86)\MySQL
• Delete C:\ProgramData\MySQL
• Delete from any Users' AppData folders. Example: C:\Users\rdoverby\AppData\Roaming\MySQL
• Reinstall MySQL

To ensure that everything is gone, I would :

1. Use Revo Uninstaller Freeware to uninstall MySQL
2. Install Agent Ransack and search for all occurrences on disk of "mysql", ".cnf" and ".conf" files and directories
3. Use regedit and search for "mysql"

Note down the directories and registry keys that you find, and then construct yourself a batch file that will do the cleanup of all the leftovers.

If you installed MySQL as a service then you may want to delete that service as well.

• Makes sure the service is stopped (should be if you uninstalled already)
• open a command prompt as administrator (start menu, search "cmd", right-click on cmd.exe, run as administrator)
• run sc delete MYSQL from the command prompt. (Replace MYSQL with the name of your service)
• open services menu and check

MySQL stores configurations in a file named my.cnf (probably called my.config on windows) try searching it on you system and deleting it.
It is usually located somewhere in /usr/local/mysql or /usr/local/var