What I did: by default ubuntu has read only ntfs support.
you can add read write support by installing ntfs-3g in the same manner as installing unrar. ----> I have use synaptic graphical package manager

Here what it say the window after installed:
$ log file indicate showdown (0,1) failed to mount '/dev1': operation not supported mount is denied because NTFS is marked to be in use.
Chose one option
Choice 1
If you have windows then disconnect the external devide.
Choice 2
If you don't have windows then you can use the "force' option for you own responsibilities for example:
Type the command line.
mount-t ntfs-3g/dev/sdb1/media/freeagent drive -0 force
OR
add the option to the relevant row in the:
/etc/fstabfile:
/dev/sdb1/media/freeagent/drive ntfs-3g force 0 0
How do i do this it sound very complected for firs time novice like me, i just wanted to read the external hard drive like I did before
If there was no error during installation then the NTFS volume can be mounted in read-write mode for everybody as follows. Unmount the volume if it had already been mounted, replace /dev/sda1 and /mnt/windows, if needed.

mount -t ntfs-3g /dev/sda1 /mnt/windows
OR
You can also make NTFS to be mounted during boot by adding the following line to the end of the /etc/fstab file:

/dev/sda1 /mnt/windows ntfs-3g defaults 0 0