can you list both Wii and GameCube games now? if so.. how?
Yes! You can use both GameCube and Wii games.
How? First, you need to update CFG USB Loader to the newest version, if you have an old version this might be difficult because on very old versions the online update feature is broken.
So, first manually update CFG USB Loader, then once you have done that go to update and update CFG USB Loader to r45/r46 using the inbuilt updater - This will require your Wii to have an internet connection (I recommend r45, it seemed most stable to me).
Fat 32 is required for GameCube games and is recommended as a hard drive format, it is most supported by homebrew.
Make sure your hard drive is formatted at Fat 32, if it is not, I recommend you use
http://www.mediafire.com/?ncoez2o4z56lxjm Caution: Formatting a Hard drive will make it lose all files on it, remember to make a backup of any games to your computer first!
Now, put the games back on to your hard drive using http://gbatemp.net/topic/188295-wii-backup-manager-for-windows/ - This will do everything you need and is recommended for all games, unfortunately it does not load GameCube games yet, but there are other methods of installing GameCube games.
Plug your hard drive in and start it up, wait a few seconds then start up your Wii. Now open CFG USB Loader, it should start up and have a list of games!