The Bricking and Unbricking FAQs has your answer. Look here:
Also this section is for actual bricks, thread moved.
I have been reading Dogeggs tutorial on soft moding a 3.1-4.1 wii,and he uses the term "brick" What does this meen actually.I am new at this. Thanks
it will render your wii useless unless you did a nand backup or can fix your problem