icacls granting access to all users on windows 7

I'm trying to give full access (read, write) to a specific folder to all users on Windows 7. The problem is that I don't know how to do that using icacls.

c:\windows\system32\icacls c:\folder /grant "domain\user":(OI)(CI)M
c:\windows\system32\icacls c:\folder /grant "everyone":(OI)(CI)M
c:\windows\system32\icacls c:\folder /grant "Authenticated Users":(OI)(CI)M

Open command window and type c:\windows\system32\icacls /?

Only these two answers worked for me:

In an Administrator Command Prompt:

C:\Windows\System32>takeown /r /d y /f f:\backup
C:\Windows\System32>icacls f:\backup /t /grant Everyone:(OI)(CI)F

(OI) is for future files and (CI) for future folders.