How to Backup a PC image using Clonezilla

Enter the BIOS settings on the PC that you are trying to save the image and go to:
System configuration > SATA Operation > Select bubble for AHCI

Then hit Apply and exit, the PC will reboot. 

Now, enter the Boot menu by pressing F12 a lot of times while the PC is booting up and the DELL Logo shows up:

Once in the Boot menu (picture below) Select the Sandisk USB drive with the clonezilla as the boot partition and hit enter:

Clonezilla will launch, select the first option:

Then select English as language:

Enter on "Keep the default keyboard layout

Enter on "Start Clonezilla":

On this screen you will select device-image to start work with partitions:

Now, enter on "local_dev" to work with a local device (The PC you are backing up).

Then press Enter again:

Now it will show you all of the partitions, here you want to make sure that you can see your destination drive (the USB where you are saving the image to) is listed, in your case should be a 128GB Sandisk:

Press Control + C to skip this after verifying your destination drive is available. 

Now, select beginner mode:

Then press enter on "Save Disk", this means you will save the image of your desired PC:

Now you need to type a name for the image you are saving:

Select "z9p zsdtmt_compression:

Enter on "Skip checking/repairing source file system"

Enter on "Yes,c check the saved image"

Enter on "-senc Not to encrypt image"

Enter on "Choose":