It is really easy to use Macrium to make an image
Download and install
Macrium Reflect freeCREATE EMERGENCY USBOnce installed run the programme
Insert a 4GB USB drive into the system
On the left of the dialogue select
Other Tasks Select
Create bootable Rescue mediaIn the window that opens select
Windows PE 5.0 Click
Next Select
Default base WIM on the next dialogue and press next
On the next dialogue select your USB drive and
enable multiboot MBR/EUFI USB support (If available)
Click Finish and your rescue USB will be created
Once the burn has finished you will be asked to test the USB
Do this by rebooting the computer with the USB inserted
The computer should then start in the recovery mode
Exit from this and remove the USB
Keep the USB safe as this will enable an unbootable computer to boot
TO MAKE AN IMAGEConnect your external Hard Disc
Run the programme and tick the partitions you wish to image (In my case I have selected System and OS )
Then click
Image selected disc on this computer at the top left
Ensure that the correct partitions are selected to image
Under destination locate and select the external drive in my case G
Click next and a summary of actions will be shown
If you are happy click finish
You will be asked to confirm the backup
Select OK
Once it has completed select close and unplug the external drive. Job done
To use the image from an unbootable computer
Start the computer with the recovery USB
Plug in the external drive and just follow the prompts