About system files

Hi all,

I want to interact with some system files in Windows, and I may write to that file by deleting some stuffs, but since they are protected from this action is there any way that makes me able to write such files without notice from windows

Thankx

Trying to write a virus or some other malware?

No, what I am trying to do is to interact with certain windows system file and want to make special software that uses that file in other system -- with the same function