I made it best practice here always to use the RSEmergencyGUI CD when recovering windows disks.
It's not only this Win 7 issue, it is also the system volume information being filled with some info from my windows installation. So if there is any data lost/deleted this alone may ruin your chances for a good recovery.
Alternative - the even better prattice - is to use a read-only device for the client disk - now as USB 3.0 has arrived the speed loss of former days USB 1 or 2 connected disks has gone. AND the devices has become cheaper - I see then at some 60$ where before they were at +250$ (forensic "class")