Some changes to system icons aren't reflected

[yutopon777]

I replaced some shell32.dll and imageres.dll icons in Windows 7 (like error icons), but some applications (notepad and etc) still show the original 7 icon. I did a clear icon cache to solve it but it doesn't take effect...
Does anyone know the cause? Thank you.

 

[LMiller7]

Icons for executable files like Notepad are usually in the application exe, such as C:\windows\system32\notepad.exe.

 

[yutopon777]

Icons for executable files like Notepad are usually in the application exe, such as C:\windows\system32\notepad.exe.

Well, I replaced notepad.exe with XP one. It displays a warning icon, for example when exiting an edited file, but it shows win 7 original icon even if I've already changed the system icons. Also some other third-party applications appear to refer to win 7 icons.
I wonder where it's being called from, and I'm wondering why the problem occurs...