The crazier thing is that the RUU won't run.
Do you have another microsd card you could try? Otherwise, I'd try yet another format to fat32 using the PC to do so. And choosing the full format option rather than the quick option. I have seen situations where people have had to reformat several times before it took...I believe 4 times was the record if I recall. Took some patience on behalf of the other party.