There is little you can do in these cases. If you still have the keys or a NAND back-up of that wii, it can be restored using a hardware NAND programmer. If you don't have a hardware NAND programmer, you can ask certain members here, but they will charge a price. If the wii is bootmii/boot2 capable, bootmii can be injected using a hardware NAND programmer. Again, other members can do this for you, but it will cost you. If you don't have a back-up or the keys of the wii and it's not bootmii/boot2 capable, there is nothing that can be done.