> A few more details about the failure mode might get you better help - > "didn't work as expected" is not very descriptive. Did you try to > reboot? What happened? What else have you tried? Can you boot from > rescue media? What is currently in /boot/...? The answer to the last question is "nothing". It was the /boot partition I accidentally did a mkfs on! And "didn't work as expected" simply means that the system didn't boot. Fortunately, my root partition an all the other partitions where not affected. Thanks to the earlier replies from Ross Walker, I was able to recover my system using roughly the following steps: 1. Boot from CentOS 4.5 CD #1 in rescue mode 2. chroot /mnt/sysimage 3. mount /dev/hda1 /boot 4. rpm -e grub kernel 5. yum install grub kernel 6. e2label /dev/hda1 /boot 7. reboot Whew! I was really sweating bullets for a couple of hours. I would have hated to rebuild this system from the ground up (the OS is the easy part as I have a kickstart script, but I've installed Oracle and a bunch of other things that would have taken days to reinstall). Anyway, thanks all for the replies, I am now up and running again. Alfred