Original post by: Thomas Padgett ,
that hard drive, does it have a partition table yet? As I stated previously you will likely need to upgrade some firmware. Here is a link pertaining to this situation: http://support.apple.com/kb/HT2434 Hopefully this will resolve this once and for all. You might have to install it in the other MacBook temporarily so you can use it's disk utility to format the new drive for GUID partition table, otherwise firmware update won't work. Let us know how this pans out for you.