After nand flash with my old nand Wiien then refuses to show any image and to start Bootmii. Then its boot its only "blue screen ".I have inst Bootmii (boot2). I have tried with 2 different SD cards but still nothing happens: (Anybody know what I can do to fix it?

Make sure that bootmii's config.ini has autoboot to "off", then try again. Otherwise you may have wiped you NAND somehow. Send it to Nintendo.