No Windows in Ubuntu boot menu (Ubuntu 11.10, WIndows 7)

Question

1. Install Ubuntu 11.10, successfully;
2. Install Windows 7, successfully;
3. Re-install grub with command mount /dev/sda1 /mnt; grub-install –root-directory=/mnt /dev/sda, successfully;
4. reboot.

The ubuntu can start up and works corrected; but the problem is: when reboot (and press Shift), there is no Windows in the boot menu.

output of command sudo fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes

255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 4096 bytes

I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Disk identifier: 0x00011272


   Device Boot      Start         End      Blocks   Id  System

/dev/sda1            2048   761927679   380962816   83  Linux

/dev/sda2       761929726   781459455     9764865    5  Extended

Partition 2 does not start on physical sector boundary.

/dev/sda3   *   781459456   781664255      102400    7  HPFS/NTFS/exFAT

/dev/sda4       781664256   976771071    97553408    7  HPFS/NTFS/exFAT

/dev/sda5       761929728   781459455     9764864   82  Linux swap / Solaris

Answer 1

Yesterday, the same thing happened to me.

I solved this issue by opening the terminal and typing sudo grub-update and then restart the system (sudo reboot).

Answer 2

If you have to set up a dualboot system machine with windows and ubuntu, the best choice is to install windows first and then ubuntu.Reinstalling the grub can lead to errors if you don't know to do it or if you forget to set up something.I suggest you to reinstall ubuntu entirely.You can solve this problem in other ways, but trust me....this is going to be the fastest one(especially if you install it from USB)