Here's a hardware tip for you. A colleague who had an older computer with Windows Vista installed bought a new computer with no operating system installed, and he wanted to move the system hard drive from his old computer to his new one to take advantage of the improved hardware in the new system. Unfortunately when he tried doing this and booted the new computer, a Stop message 0x7b was displayed that indicated "Inaccessible Boot Device." So he returned the hard drive to his old computer and investigated this further.
After some additional investigation he discovered a way to resolve his problem: he opened Device Manager and configured his old computer to use the generic Microsoft Standard IDE Controller driver instead the currently installed vendor's IDE controller driver. Once this was done, he shut down his old computer, removed the system drive, inserted it into his new computer, booted his new computer, and everything worked. He had to reactive Windows of course because of the hardware changes.
If you have feedback concerning this tip, I'd love to hear from you.