So I've decided I need to upgrade from my 2ghz Blackbook to a Macbook Pro. Luckily for me my girlfriend bought the latest Macbook Pro 2.2ghz right before she started grad school in September. She realized that she didn't need all that power and wanted something smaller since she has to lug it around campus a bit. So the trade was an obvious solution for both of us (yes, I am giving her a bit of a financial incentive). Here's my question. I just put a new 250gb drive in my mac book and I want to keep that because I need the space. So, can I just put my HD in the macbook pro and hers in the macbook and be ok. Will I need to reinstall the OS so its optimized for the correct computer? I installed a hd in my old PB g4 back in the day so I am not worried about the installation. Also, I have leopard, but I will be upgrading her to leopard once the HD have been swapped. Thanks for the help.