Strangely, this one turned out to be a viral-marketing "hoax" (http://meta.serverfault.com/questions/8696/what-to-do-with-the-rm-rf-hoax-question). The 123reg one is real. Discussion on the latter here:
I managed to delete a whole dealing room FX system many years ago. All the transactions, programs the lot. It took several days to recover and get back to normal operations.
Someone changed the wires on the back of my dedicated testing PC when I was on holiday. When I came in to work, I sat down at the terminal to practice a new install. My first action was to delete the system and then begin the install. I deleted the entire live system in about 30 seconds.