I have an ASUS-K55V. I had a dual boot with Windows 7 and Ubuntu 12.10.
Recently I upgraded my Ubuntu from 12.10 to 13.04 using the do-release-upgrade command. The update went fine, but after the update when i tried to boot into windows, it gave me an error, and restarted. Then i used a windows installation USB and used the repair commands
bootrec /FixBoot
bootrec /FixMbr
When my machine booted this time the grub menu didn't show up, so i used a live Ubuntu USB to recover my Ubuntu. I used the boot-repair tool suggested at Ubuntu Sharing.
Now I got my 13.04 back and i ran the update-grub2 command to recover my Windows, but it does not detect Windows 7 now. I tried using my Windows 7 Installation USB to use the Repair option, but even there it does not detect Windows 7.
Next I added the boot option myself by the procedure given at this Post, and this Post, yet there is no menu entry for windows in my grub.
Please help me to fix this issue.