It can only change the icons on your taskbar and start menu. That is it.
It cannot change the icons that appear in Explorer (hard drive icons, disk icons, My Computer icon etc.) or the Control Panel. These icons are stored in special system DLL-files. 7CONIFIER does not mess with system DLL-files; hence, it cannot change these icons.
7CONIFIER works with any icon-files. You may have to create your own package though, and assign custom icons to the programs that appear on your taskbar and start menu. This is quite easy. If you speak Spanish there are plenty of tutorials on YouTube (the internet is a wonderful place).