Dual booting Ubuntu and windows 7

Question

I am trying to dual boot Windows and Linux on a machine at work. While I haven't used windows in a while, It is a process that used to work most of the time. But I haven't been as lucky with this particular machine.

This machine is running Windows 7 with Ubuntu 12.04. After the Ubuntu installation grub never appears and the machine boots to Windows 7. So far, I have tried manually booting Ubuntu from the usb stick and installing grub again without success.

To help see my configuration, here is a partition layout.

 Disk /dev/sdb: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disklabel type: dos
 Disk identifier: 0x862b0218

 Device     Boot     Start        End    Sectors   Size Id Type
 /dev/sdb1  *         2048     206847     204800   100M  7 HPFS/NTFS/exFAT
/dev/sdb2          206848  614399999  614193152 292.9G  7 HPFS/NTFS/exFAT
/dev/sdb3       614402046 1953523711 1339121666 638.6G  5 Extended
/dev/sdb5       614402048  814399487  199997440  95.4G 83 Linux
/dev/sdb6       814401536 1953523711 1139122176 543.2G 83 Linux

Also the bios is using legacy mode and secure-boot is disabled. Apart from that it looks like re-installing grub didn't work, because the first 512 bytes are different from my laptop which has grub installed on mbr.

Any ideas?

Answer 1

There's a tool that easily recovers/install GRUB to the MBR. http://www.supergrubdisk.org/category/download/rescatuxdownloads/rescatux-stable/ . Just burn the CD image to either a CD/DVD and boot from that disk. In the application window there's a GRUB category, click on "Restore Grub", then follow the instructions.

There's also a youTube video in that page that explains this process, amongst a lot of other things. http://www.supergrubdisk.org/rescatux/

Word of advice, if you check their video, make sure your speakers/headphones are set at a very low volume at first, then gradually increase it as needed, your ears will thank you for that.