Comment 3 for bug 742967

Ruled out ntfs corruption with CHKDSK. Then I installed 10.04.2 wubi and it boots fine on /dev/sda3. So there appears to be something about the Natty where /host is not the main Windows partition.

PS before I removed the Natty install, I ran updates and it stopped booting again - dropping at the grub prompt.

This is the section of grub.cfg that differs from a lucid 10.04.2 grub:
function load_video {

insmod part_msdos
insmod ntfs
set root='(/dev/sda,msdos3)'
search --no-floppy --fs-uuid --set=root 8654915254914639
loopback loop0 /ubuntu/disks/root.disk
set root=(loop0)
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=auto
  insmod gfxterm
terminal_output gfxterm