Bonjour et merci pour votre aide (à 77 ans, je suis un perdue !) Clean Up Premium a trouvé 10 problèmes et pour les résoudre, il,me propose simplement d’acheter Anti Track !
Whilst we do not know what problems you have been warned about, I suspect this is an example of an Avast product “upselling” another one of their products, by worrying the user (scareware).
I do not use Avast Clean Up or any other proprietary “Cleaning” software as it often does more harm than good IMO.
If you use Firefox webbrowser it includes Enhanced Tracking Protection options built-in. You can also install uBlock Origin as a browser add-on for more protection.