Nintendo Wii: Where are my "blocks" of memory?

When I go to “data management,” the sum total of everything listed there comes out to only about 200 blocks, but it also says I only have 100 blocks free. For a total of about 300 blocks. Yet the Wii is supposed to have about 2000-3000 blocks available total.

Does anyone know where all the other blocks would be? My kid just got a Gamecube Controller and now I want to download a bunch of gamecube and SNES games and can’t because no blocks!

I seem to remember there being more free than that when I got a Wii, but maybe system updates are taking up all that space now? Maybe if you remove some of the optional channels it will open some space?

Anyway, the simplest thing might be to throw in an SD card and use that instead. The Wii only has half a GB of internal storage, so even a little 2GB SD card should be more than enough space.