Apparently, CCleaner 4.x is no longer compatible with Windows 2000. (I don't know that it WON'T work, just that the installer prevents it from installing.) Version 3.28.1913 is the latest pre-4.x version listed in the release notes, so I'd like to download it and install it on my Windows 2000 virtual machine. But I cannot find a link to any archived older versions anywhere on the Piriform website.
If Piriform has chosen to end support for earlier versions of Windows, that's their right. It's a free program, after all. But it would be a decent gesture to keep available the latest versions that WILL work on older OSes.
I may not be able to use the latest and greatest version, but I should at least be able to obtain the latest version that will work for me.