Possible Duplicate:
Grub rescue - error: unknown filesystem
I have had bad experiences with 12.04 on my laptop, too many things just don't work so am wiping it and replacing with Windows 8 release preview to get it running again. Anyway, I installed normally, deleted partitions and formatted and installed Windows fine, but now there is an error coming up when it boots:
error: unknown filesystem
grub rescue>
I've tried repairing from Windows 8 disk, doing FixMbr and FixBoot but that hasn't worked, and neither has reinstalling.
Any ideas how to get rid of this?
sudo fdisk -l
and post the results on your question.