Then you should back up the data stored on the drive as it is unreliable. Bad sectors will continue to appear.
In case the drive is still under warranty, you can contact WD's Support either by e-mail or phone and eventually RMA it.
In case it is not under warranty, my advise would be to get a new drive and use the current one for storing non important data.
WD's Support:
http://products.wdc.com/support/kb.ashx?id=N6X0AY
Hope this will help,
D_Know_WD