Explanation/Reference:
Explanation:
A hard-link migration store enables you to perform an in-place migration where all user state is maintained on the computer while the old operating system is removed and the new operating system is installed; this is why it is best suited for the computer-refresh scenario.
http://technet.microsoft.com/en-us/library/dd560753(v=ws.10).aspx
Refresh Scenario
Similar to a new installation, the refresh scenario performs a clean setup. The difference is that the target computer already contains Windows, for which files and settings will be preserved (installed applications are not taken into consideration). This scenario is especially useful in the event that preserving the user state is a priority. It still leverages the consistency benefits that come through a new installation. You can automate this scenario with the latest version of the User State Migration Tool (USMT 4.0), which will collect pertinent data for each user state found in the system, and restore it after the clean installation is performed.
Replace Scenario
This is similar to the refresh scenario, except the target system is a new computer that does not yet contain any files or settings. The scenario consists of conducting a new installation on the target computer, and then using the USMT 4.0 to transfer files and settings from the old computer. You can run this scenario side-by-side with an older system running Windows XP or
Windows Vista.
http://technet.microsoft.com/en-us/magazine/hh124549.aspx
Hints:
Install on existing client computer = refresh
Replace a new client computer = Replace