Automatic FTP backup program

What we need is a backup program that automatically backs up our clients file to our website server (it also accepts FTP). The program should do it automatically, if the client wants to do it daily, weekly, or monthly. On a time that they set. Also if the backup was missed it will automatically do it the next bootup or something like that (this is NOT a must but would be great). We have on our website’s server 400 GB available. It should not be a custom program, it can be a freeware program or something like that, but still you will have to make it work before you advise that one. You will get our passwords and account information for you to check if it is working. It really should not take you more than 2 hours to do this. We don't want to pay for the program because will be installing it on lot of computers. Once again thank you so very much, Anthony Martina