just to add to what Mr. DeadlyFoez said, if u don't have bootmii as boot2, i would avoid using comex's nand formatter unless it is a last resort to fix a bricked wii.
In your case, there should be less drastic measures to solve your problem, but if u have bootmii as boot2, and a nand dump, u will be safe using the nand formatter for sure
Goooooo "TeamYour Mom"!