[stomachmonkey]

Put in the new drive.

Get an external SATA case and put the old on in there.

If it mounts and you can get your data off then try re formating the old drive. If it just has bad sectors you can lock them out of the allocation table and continue to use the drive. If any of the drive mechanism is physically damaged you may not get your old data back anyway.

Do you have access to a desktop with internal SATA connectors? ou could always slap it in there.

Little Apple plug here. Mac laptops have a sudden motion sensor for exactly this purpose. If it reads acceleration and/or abnormal orientation it immediately parks the read/write heads to prevent drive damage/data loss.