When you type in the windows run dialog "calc"(for example), Windows know which program to execute because it has in the registry the link associated with the word "calc"(usually windows/system/calc.exe).
With this application you can make other connections. Let's suppose that you have the program "C:Program FilesMax2k LogicMaxKeysMaxKeys.exe" and want to associate a short word. Type a command(e.g."key") and open the file.
Then click the "Add/Update" button.Now , every time you'll type "key" in the run dialog the MaxKeys program will be executed.