A new computer has arrived and has Y'z shadow installed. I want to uninstall it but a search doesn't show any such programme. I've looked on "Add/Remove" and I've used CCleaner to try and find it without success. Ideas, please.

Did you look in Explore under Program Files for the actual program itself and manually delete it? Or, do a search in explore for it. Also try MSCONFIG to see if you can disable it there. Also try Administrative Tools/Services to see if you can disable it there.