12.04 - Grub Rescue set on partition that doesn't exist

I recently got a new laptop with Windows 7 installed. I downloaded 12.04 LTS ISO and created a bootable USB stick. I booted into Ubuntu on my laptop and installed Ubuntu, choosing the 'side by side' option for Windows and Ubuntu.

Now when I boot I get this error and a Grub rescue prompt.

error: no such device: f0e797ec-17f0-4777-8296-1a44b8524753
ls
(hd0) (hd0,msdos4) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (hd1) (hd1,msdos1) (hd2) (hd2,msdos5) (hd2,msdos1)
set
prefix=(hd0,5)/boot/grub
root=hd0,5

Notably, a set command returns partitions that don't exist when I do an ls.

Furthermore, when I do an ls on all of the partitions shown above, they all return 'unknown filesystem'. Which I take to mean that none of the partitions are linux partitions.

Any idea what the heck might be going on here?