DLL File reverting to its old version in system32 folder

[Guest]

Am developing an application in VS.

I am creating a dll library file. And I want windows to use my library file,
instead of its own. But as soon as I replace the dll file in windows/system32
with my own, it is automatically changed to its original version.

This is probably a security feature but,
Could you please tell me how do I disable this?

 

[GTS]

Fortunately Windows XP prevents that kind of completely unacceptable
programming practice as described in
Description of the Windows File Protection feature
http://support.microsoft.com/kb/222193