To recover from a windows installation first we need to boot from LiveCD of Ubuntu if you installed with system 32-bit use 32bit Live CD If 64bit use 64-bit live cd.
Mount the Linux partitions using
sysadmin@localhost:~$ sudo blkid
[sudo] password for sysadmin:
/dev/sda1: UUID="846589d1-af7a-498f-91de-9da0b18eb54b" TYPE="ext4"
/dev/sda5: UUID="36e2f219-da45-40c5-b340-9dbe3cd89bc2" TYPE="swap"
/dev/sda6: UUID="f1d4104e-22fd-4b06-89cb-8e9129134992" TYPE="ext4"
Here my / Partition is /dev/sda6, Mount the / partition to /mnt location.
# sudo mount /dev/sda6 /mnt
Then mount the Linux access points, Linux devices, proc, sys
Linux device
# sudo mount --bind /dev/ /mnt/dev
proc system information
# sudo mount --bind /proc/ /mnt/proc
Kernel information to user space
# sudo mount --bind /sys /mnt/sys
If we need to enable the networking we need to do the following steps.
# cp /etc/resolv.conf /mnt/etc/resolv.conf
Change the Linux root to be the device we mounted earlier in step 2
# sudo chroot /mnt
Then install the grub to write the new master boot record, Never point the partition to write the grub.
# sudo grub-install /dev/sda
This will fix the dual boot issue.