Installation iis on windows server 2008r2

i try to develope my site on a new installation of windows server 208r2 with iis e mssql server 2012.
I have a problem to save the connection config (tested ok)
i read the advice:
For Windows Servers using Web IIS Server, is necessary to define the permissions in the directory _lib (common libraries), and in the CMD files (C:\WINDOWS\system32) for IIS users (IUSR_NOME-DO-SERVIDOR) .
In the _lib directory i have set the full control ti iusr… but i can’t change the permission in (C:\WINDOWS\system32)
How can i do this setting? → CMD files (C:\WINDOWS\system32)
Someone can help me, please