Do you mean use the new drive as the windows/boot drive? If so, Install the new drive, disconnect all other drives. Insert the win8 install disk and install to the new drive. You will need to reinstall all drivers & software. Reattach other drives once the new win8 drive is functioning as expected. At this point, you can reformat the old drive and use it as secondary storage.
Other option: In order to keep the OS, programs, & configuration, clone the old drive to a new drive. Use the bios to assign the new drive as the boot disk Once you're satisfied all has gone well, you can reformat & reuse the old drive. Search the forums for cloning a drive. There are plenty of topics about it.