Hi there doohbacles,
I believe this should be an internal drive right?
Have you tested the drive? In case you haven't it may be a good idea to do so:
http://www.tomshardware.co.uk/forum/282651-32-best-diagnostic-testing-utility
I believe you can use some brand specific tool as well.
Another thing you can try is to use different cables(SATA and especially power ones) and attach the drive to a different port.
It is always a good idea to have a back up of your most important data, even when you are not facing HDD related issues.
Let us know how this goes,
D_Know_WD