I have got a machine with dual-boot Windows 7 and Ubuntu 11.10, and I wanted to add another OS to that (Jolicloud), so I started the partition manager in Windows and shrunk the Windows partition by about 10 GB (so now I have:Windows;currently empty 10GB;Ubuntu). I shutted down the computer because I was finished. Now when I started my machine again it says
error:no such partition. grub rescue>
and I can type commands.
(hd0) (hd0,msdos5) (hd0,msdos4) (hd0,msdos2) (hd0,msdos1) (fd0)
if that helps