I am using a Wubi installation installed through Windows 7. I have lots of problem with grub and nothing is working. I have important files in the partition. I can boot through a live CD if necessary.
Here's the pastebin link to boot-repair.
where sdX is the label for the HDD where Grub will boot from.
You should be fine, just reboot the PC, eventually, after booting Ubuntu from your HDD, just run