How to install Dig on a Windows 8.1 64-bit system
This installation procedure will extract only relevant libraries and executables from the BIND 9 package, and not install a full-blown DNS server. The installation method is also applicable on Windows 7 64-bit systems.
Head over to http://www.isc.org/downloads/ and download the BIND 9.10.0-P2 package. Select the 64-bit version and leave the 32-bit package as a last resort. The 64-bit version is dependent on the Microsoft Visual C++ Redistributable package, which you can download and install from http://www.microsoft.com/en-us/download/details.aspx?id=30679#