Do NOT UNISTALL any ios, cios, or system menu files.
But if you installed a wiiware, vc, or some other wad that would install a channel for you- this is what is probably causing the problem.
Now with that on the card hold reset and boot the wii- preloader should load
load boot.dol- wadmanager should start
Use ios 249
Uninstall the last wad you installed- so long as it was not a ios, cios, or system menu.
Then restart the wii, if it is fixed- great, if not repeat the process moving to the next wad you may have installed.
How many wads did you install? What where they?
Don't forget not to uninstall any ios, cios, or system menu as you wont like the results.
Let me know if you have any questions.