Hi!
NCH Software installers are generally very small in size. The link MakubX posted is from the official "old versions" archive page of NCH Software.
If you have a registration code from the past, kindly make sure that you temporarily disconnect your computer from the internet while running the installer, so that the old version installer will not auto-update.
Please let us know if there is anything else that we can assist you with. Thank you for your continuous support.