I uninstalled CCleaner, but I have troubles with it, because everyday it appears in my Task Manager (Windows 10)
How can I kill it?
It sounds as if you have a scheduled task left over from the uninstall. Probably the Update Task.
Run the Windows Task Scheduler, on the left select the 'Task Scheduler Library', and see what CCleaner related tasks are there.
Highlight the task and on the right select 'Delete'.
Then take a look in your 'tasks' directory and see if you have the following, (or anything else relating to CCleaner), and if so then delete it -
C:\Windows\System32\Tasks\CCleaner Update