Can I safely delete everything cc says is a problem,especially from the registry.
Even if I save registry before deleting I would not have a clue how to put them back!
thanks.
As you have noticed ccleaner prompts you to make a backup, this is saved by default in ''my documents''
In the event that you need to restore them you would right-click and choose merge.
More info here
http://docs.piriform.com/ccleaner/troubles...ve-run-ccleaner
If you have other problems (say you have had a virus etc) it is best not to think that this would 'solve things.