Hi,
Thanks, everyone, for your replies.
Hazelnut: I tried "Safe Mode" but it still wasn't listed in "Add or ..."
Forte Lambardi: I tried the ZSoft "Uninstaller" but, although it seems to be a superb program, CCleaner still wasn't listed.
Keithuk: Thanks for the welcome. I've downloaded and installed the latest version and everything seems to be going swimmingly; CCleaner has even returned to "Add or Remove..." list. One of the reasons I didn't do this, before posting here, was that, as the initial "removal" via "Add or Remove..." hadn't worked, I feared trying to remove the program may have damaged it and what would be the point of installing a new version over a damaged version?
I didn't want to suddenly discover, for example, all the files I'd securely deleted hadn't been deleted, due to a fault caused by messing around with "Add or Remove..."
Anyway, I haven't detected any problems, so far.
Thanks.