SID duplicating issue: Here comes NewSID
Security Identifier – or SID is a unique number to determine a unique object (user, group, USB device, … or even a computer). Once you duplicate a hard disk using raid mirroring, cloning, ghosting :D … You may face this problem, the SID of your PC is duplicated, you will get a lots of trouble with your network/system.
NewSID is a free tool from Microsoft, to change hostname, SID, IP address, … of an duplicated PC. You can go over this link for more information and download: http://technet.microsoft.com/en-us/sysinternals/bb897418.aspx