These instructions are for Handbrake 0.10.0.6534 (64 bit) Windows.
First, install Handbrake. You can get it from https://handbrake.fr/ .
Second, download libdvdcss-2.dll from http://download.videolan.org/libdvdcss/1.2.11/win32/libdvdcss-2.dll (32 bit version) or http://download.videolan.org/libdvdcss/1.2.11/win64/libdvdcss-2.dll (64 bit version). The version that you need depends on whether you installed the 32 or 64 bit version of handbrake.
Once it has downloaded, move the libdvdcss-2.dll into your Handbrake install directory (usually C:\Program Files\Handbrake\).
That's it! You should now be able to run handbrake and access encrypted DVD content.
So what's wrong with all the other instructions out there on the web?First, their links to libdvdcss-2.dll are broken; they all have an extra 'pub' element in the URL that no longer exists.
Second, they tell you to rename libdvdcss-2.dll by removing the '-2' from the filename. This no longer works.