with the ide disks the master goes on the end of the ribbon cable with the slave in the centre one. Once acronis has finished switch off the pc and change the jumpers on the 2 drive. Make the new one master and connect to the end socket on the cable. Make the small old drive the slave and connect to the centre connection. Switch on and the new drive should now be seen as C with the old one as F. All should now work fine. Keep the old one as the slave for a while in case there is something that did not get copied.