The free demo available is fully functional except that it will only allow you to use the program for 60 days. Try it out freely and experiment to see if it meets your needs. If so, when you purchase the program, all of the data you have entered will be unaffected and you can proceed from there. Additional information on the program is provided in the documentation file, which is also available here to provide additional information for those interested.
Download The Birthday Program V 1.0 Demo - bpsetup.exe here.
To download, right-click and save the file to a directory on the machine on which you want to install it. Be sure to read and print out the online documentation including that on installation before trying to install.