I just bought an HP ZE 4145 notebook computer that needed repair. When I turn it on, it comes up with an error message - PXE-E61 Media test failure, check cable and then Operating system not found. I tested the hard drive on another computer but couldn't get anything to come up on it. So I got another hard drive but it still does the same thing. I tried taking it apart and removed all the screws underneath but it wouldn't split apart. Does anybody have experience with these? I have built my own desktop unit but this is my first notebook. Any help would be appreciated.