Cant type backslash on Open Firmware

Hello there, I have burnt a Debian CD to a dvd (yeah I know) but when I hold down c - nothing. open firmware - boot cdrom - nothing. I saw somewhere that you could point to yaboot (boot cdrom:,/boot/yaboot) but when I press the backslash key, it deletes it down to boot c. Can someone help? If it helps anyone, I'm using a Dell USB keyboard.