Chancing to an other computer

My old computer (this) is going to trash because it is too old. What must I do to move me ccleaner from this computer to the new computer. I have CCleaner professional

You can transfer your key to a new machine quite easily.

On the new machine download CCleaner Free from here: CCleaner - Download Builds
Double click the downloaded installer to install CCleaner Free, and then activate it to Pro by entering your existing licence key in Options > Licence Key.

You can see your existing key in the Options > Licence Key in your current CCleaner Pro on your old machine.

Once you have activated CCleaner Pro on the new machine then, unless you have a multi-device licence, you should uninstall CCleaner Pro from the old machine.

Than you very much of your good information