Reformatting the disk would fix any non physical errors. The current errors on the disk could be as a result of unplugging the disk while it was still writing data or other software errors, or it could be that the disk is starting to fail. I would recommend that reformatting a disk is done by someone that understands the process.
Be careful, if you are not sure what you are doing you could inadvertently reformat your internal HD rather than your external backup WD drive.
