The best place to install Citation Checker is the Office\Startup or WORD\Startup folder. You install the program by copying the file to the folder.

By default, that folder is located in Program Files\Microsoft Office\Office (or Office xx)\Startup, or perhaps Program Files\Microsoft Office\Office (or Office xx)\Word\Startup. When Office was installed, an option to change that location was available. If the option was exercised, you need to find the Startup folder.

For WORD versions before 2007: You can always find the location of the Startup folder via the Tools Menu in WORD. Navigate your way through Tools, Options, File Locations, Startup.  When you next restart WORD, Citation Checker will appear as an item in the Tools Menu. To use the program, simply click on Citation Checker while your manuscript is on the screen.

For WORD 2007, life is a little more complicated. The Word/Startup folder may be a little hard to find. For the Vista operating system, the default location is the rather obscure (Your Username\AppData\Roaming\Microsoft\WORD\Startup. With your manuscript on the screen, access Citation Checker by clicking on Add-Ins, then run Citation Checker by clicking its name. If Citation Checker does not appear when you click on Add-Ins, the problem is surely that you didn't find the correct place. 

The version of Citation Checker you download from this site has limited functionality. When you have purchased your personalized license, you will receive a license file that should also be installed in the same folder as Citation Checker. Installation of that license (simply copy it to the folder) will unlock the full set of program features. 

The personalized license grants you the right to run Citation Checker on your home, office, and laptop computers. You may not transfer the license to another person, nor share it with others in your organization. The price of the license is $25 USD. The license will have your name attached to it.

The security settings in WORD are designed to protect the computer from unsafe macros. When Citation Checker is installed, WORD may be unhappy and warn you about the impending invasion. You can get rid of that warning by changing your security setting (via Tools, Macro, Security) to "LOW", but that is not recommended because there are bad macros out there.