Hold in reset while powering on the wii and see if preloader comes up. If preloader comes up, then it can be fixed. Another thing you can do is when you turn on the wii, you should get a blue long flash from the drive which is normal. See if you get 2 quick flashes after that. If so, then you have bootmii installed which is installed as boot2. I am not sure though if bootmii would be much help if there is no nand backup ran for it.