Originally Posted by abriejo
I was about to try the CD startup when I tried one last thing again.
sudo mdadm --stop /dev/md0
It worked, but I find it strange because I did it before and md0 did not appear in the fdisk -l screen.
Immdiately after that I was able to run the sudo mkfs.ext3 /dev/sdc
Maybe it is because I ran the zero-superblock tasks overnight - something that made me nervous, since I have no idea what it does.
Than You for your help!
It worked for me. Thanks!