Back-up trouble (yellow bars)

I am so not a technical person and was advised to get an external back-up drive with my new laptop.  I have the WD My Book Essential 500 GB.  It was an automatic installation (which I loved) but it no longer appears to be performing the back-up from my laptop to the external drive.  There used to be an indicator arrow showing that the back-up was occuring but that no longer displays.

I notice an increasing amount of yellow bars and tech support said it meant things were awaiting back-up transfer and would occur when the computer is idol.  Well… that has not happened and I am one unhappy camper.  Any advise would be appreciated.

Thank you.


Thread moved to WD External Drives: My Book for PC.