The New Way to Look at Users Properties

The Active Directory Administrative Center is another new component introduced by Windows Server 2008 R2. Many admins gave it a glance, thought to themselves "another ADUC, why bother?", and went back to their familiar old tool. If you like acctinfo.dll though, you should like ADAC.

With Win7 RSAT installed and the AD tools enabled (or RDP'ed into your Win2008 R2 servers for AD administration), run DSAC.EXE. You'll see this:

Here is the detail explanation from the expert http://blogs.technet.com/b/askds/archive/2011/04/12/you-probably-don-t-need-acctinfo2-dll.aspx