Hi everyone First of all, thanks for reading this thread and helping me out. So I want to upgrade my internal HD because I don't want to lug an external HD around. Planning for this, I decided to call what I call my Apple store because we only have a CompUSA in the area. They have a certified Apple Representative and I asked to speak with him. I went into the conversation assuming that the MBP could only hold one internal HD, but he asked, why are you wanting to take your old one out? It isn't fried or malfunctioning is it? And I replied, no, its perfectly fine. He said, well it would be cheaper if we didn't have to take the one you have in there now, plus you can just add onto your space with this. So then I confirmed that we were talking about a 15" MacBook Pro CD and he said yes. I have asked a few mac friends and I am utterly confused now. I wanted to ask everyone here so I can get this resolved. I know he is Apple Certified and everything, but I didn't think that was possible to have more then one internal HD. Thank you guys for all of your help!