We took an Amrada E500 laptop with a 4Gb hard drive and removed the hard drive. We then placed a 12Gb hard drive in the laptop and tried to turn it on, and nothing. There is no response, no lights, no BIOS, no activity. I have seen this on a Dell laptop before too but what are the causes of this? It is like adding a different hard drive disables the entire machine or something. Any thoughts? Thanks