I stumbled across your this thread while solving a similar issue for my gf not being able to log into her school website tonight. Did you by any chance update Java?> (It can happen automatically) Anyways, I fixed the problem by
1)copying the URL of the website i needed to go to
2) Open the "Configure Java" app in the Java folder (start, all programs, Java)
3) Click on "Security Tab"
4) Click on Exceptions
5) Click on add exception and click on the white box until you can type, then paste the URL
It may warn you that it is unsecured, im not sure if Mybook supports SSL, im sure they probably do, in which case add an s in front of http (ex https:/./. www.google.com))
I dont own a WD HD but i hope this helps!!!