I had someone send me a Wii for me to fix with a similar issue. When I got it, it didn't show any problems as he described. I shipped it back to him and he finally discovered it was a bad remote. Lesson learned for the both of us on that one. So before you do anything make sure you try a different remote.
If that doesn't help then follow this guide here (cBoot2 option) to update/reinstall all your IOSs and see if that solves it.