... tried to open CCleaner ... would not open ... tried to uninstall in order to reinstall ... cannot uninstall ... the uninstall function hangs up and does not complete,saying it cannot load various files ...AND THE UNINSTALL FUNCTION WILL NOT CLOSE
Try looking in taskmanager and ending task of anything related to CCleaner.
Also go offline before running the uninstaller.
What operating system are you running ?
As well as Hazelnut's suggestions.
If you are using an antivirus other than Windows Defender then what is it and what version is it?
PS. You do not need to uninstall CCleaner before reinstalling it.
Download the latest installer from the builds page: <a href="https://www.ccleaner.com/ccleaner/builds" ipsnoembed="true" rel="external">https://www.ccleaner.com/ccleaner/builds</a>
Double click the downloaded installer to reinstall CCleaner over the existing one.
If the Uninstaller still doesn’t work after those fixes then you can try Revo Uninstaller free & uninstall it with that. The good thing is that if the Uninstaller still fails you can still scan for leftovers which will force uninstall CCleaner. Then install a fresh download of CCleaner.