You can fix those without any problem. They are all related to applications that are no longer installed. It can also arise after some update when the new version no longer use some older components.
missing shared dll: Left over from an unstalled application.
unused file ext: Another left over.
invalid or empty file class: Related to the aqbove.
activex + installer issue: An uninstaller left references to itself after use.
installer ref. issue: Same as above
old start mem. key: Left over from an unsinstall
missing start up software: Same
Electro
August 2012