If you want to replace the 160 completely with the 500, install the 500 as a slave and just mirror the 160 over to the 500. You will need drive imaging software to do this. I used Western Digital's Data Lifeguard Tools to mirror a drive that was going bad( bearing was screaming) and it worked perfectly. If you want to just add it in along with the 160, just do what cboucher said and copy only the files that you want.