My windows doesn't boot. Here is a screencast. https://plus.google.com/104553781986069868504/posts/ddRjsxuvtUi
For some special cause, I had two concurrent windows 7 installations and a version of ubuntu (grub boot broken).
How I broke my boot
My computer is configured to work with UEFI (I speak here with boot) so notice that's there is NOT a story about MBR (I think), there's more interesting things about MSR, GPT and EFI on the web...
I tried to install Ubuntu with deleting one of the two windows partitions. This broke everything because Ubuntu doesn't support EFI installation yet. I used the Linux Secure Boot livecd to repair the linux boot. It worked... But I needed to modify the windows loader part to have a fully work installation.
Here is a description of what I did: http://wiki.nekland.fr/index.php/Grub_2_efi
But as you can see on the video, my windows start partition seems to be buggy. I saw two windows and no one works.
(I have an image of my disk if it can help but I can't post it right now)
Thanks for help !