Why the trouble to fix Ubuntu boot using Windows tools if you can use Windows to download and burn an Ubuntu Live CD/USB and then use it to easily fix your boot?
Step by step would be:
- Using Internet Explorer (or any other browser), got to
http://www.ubuntu.com/download and download an Ubuntu ISO image. Any image will do it, it doesn't matter if it is or not the same version you have installed
- Using your favorite windows cd burner software (Nero? Windows
Explorer? Or try this free one), burn that ISO image to a blank
CD. Or download pendrivelinux and burn it to a USB key.
Boot using this CD/USB, open a terminal and type:
sudo mkdir /mnt/ubuntu
sudo mount /dev/sda2 /mnt/ubuntu
sudo grub-install /dev/sda --root-directory=/mnt/ubuntu
(that's assuming your boot hard drive is
sda and your ubuntu partition is
sda2. Numbers and letters may be different in your system, so check this answer for detailed information)
Your boot (and grub menu) will be restored. You can stop here, but it's recommended that, after booting Ubuntu, to issue a final touch: