Fixing issues with the registry

Is it dangerous? Can I mess up my registry? I don't really want to fix all issues unless I'm pretty much guaranteed it won't mess anything up. It finds the following issues:

Missing Shared DLL

Unused File Extension

Invalid Default Icon

ActiveX/Com Issue

Open With Application Issue

Application Paths Issue

Help File Issue

Installer/Uninstaller Reference Issue

Old Start Menu Key

Missing MUI/Shortcut Reference

When you choose to fix issues you are offered the option to back them up.

If you say yes, you can save them in your documents and then in the unlikely event of there being a problem afterwards, just double-click on the backup and select merge. They will be restored.

OK, I've just done that and everything seems to be OK. Does that mean no damage has been done or after a few reboots can problems start to happen?

ccleaner doesn't as a rule create damage after an issues scan!

I have never had any problems with mine. If you keep your backup for a week or so and then you could delete it if you see no problems (which I doubt you will)

OK thanks for the advice Hazel