Recovering the data from a failed WD My Book NAS drive
Solution 1:
the Western Digital MyBook NAS drive has a reset button (the tiny hole between the power connector and the ethernet port). this will reset all settings to facory default. run the wizard to reconfigure the drive to your requirements.
if this doesn't help, as mentioned previously, remove the SATA drive from the enclosure and connect it to the sata port of your computer or any USB > SATA adapter/enclosure.
Solution 2:
You could always extract the drive from the NAS and get a simple external drive enclosure so you can re-access your data.
I'm not sure how 2.5 Sata drives work, but you may be able to just plug it in to a free SATA port inside your PC (if not, they probably make cheap adapters to let you do so)