I'm using a registry cleaning tool, what do these things mean?

Hey there, using CCleaner's registry cleaner, there are things I don't understand. Here is a list - 1. Missing Shared DDLs 2. Unused File Extensions 3. ActiveX and Class Issues 4. Type Libraries 5. Applications 6. Fonts 7. Application Paths 8. Help Files 9. Installer 10. Obsolete Software 11. Run At... show more Hey there, using CCleaner's registry cleaner, there are things I don't understand. Here is a list -

1. Missing Shared DDLs
2. Unused File Extensions
3. ActiveX and Class Issues
4. Type Libraries
5. Applications
6. Fonts
7. Application Paths
8. Help Files
9. Installer
10. Obsolete Software
11. Run At Startup
12. Start Menu Ordering
13. MUI Cache
14. Sound Events
15. Window Services

Obviously these don't all have to be answered but preferably the main ones. Thank you for all answers. :)
4 answers 4