You have not provided enough information to receive a helpful answer HawkI007. How are the two 160GB drives configured? Is one drive used for the operating system and the other for data? Are these drives configured as a RAID mirrored pair? Or are both of these drives configured as data drives and the OS installed on a 3rd drive? I will often use
Clonezilla to replace/swap-out drives. Clonezilla is free and it works very well, but the user interface isn't very friendly, although I haven't downloaded the latest version as that may have changed by now. I'd suggest you describe your drive configuration a little better to the guys here can help you.