So I've got a new HDD which I'm replacing my old one with - however I can't boot or even access data on the new HDD when it's connected with the internal connection of my macbook. It works perfectly when connected externally - I booted from it I'm using it now and I'm yet to have an issue. When I have it internally the disk image is renamed from 'Mac2' to 'disk01s' and it reads that it has 19MB stored on it rather than the 230GB that is on it when I connect it externally. When attempting to boot with it internally I get the flashing file and question mark error - I thought it was an error with the HDD but I repaired it with disk utility and nothing came up, and it connects fine externally. My old HDD can boot and work connected both internally and externally. The 750GB does not appear in system preferences -> startup disk when it's connected internally, but as I said before if connected externally it's the default startup disk. Both are running 10.6.8, but I'm really not sure what info is relevant to this issue. 2GB RAM, Intel core 2 duo processor, I haven't changed anything graphics-wise. Does anyone know what this is or how to fix it? I'm pretty lost at this point.