If it were that easy, wouldn't Microsoft have been able to do it for the 360?
Since the original XBox was built with off-the-shelf x86 components, successfully emulating basic functionality on a PC should (in theory) be easier than doing so on the 360, where they moved to Power PC. It's a totally different CPU structure and uses different instruction sets, meaning some amount of translation of the machine code would be necessary that (again, in theory) shouldn't be needed on an x86-based PC.
Of course, there's always the nvidia north/southbridge and video card to worry about. You know that there's no way NG was programmed using DirectX. I'm 100% sure they hand-coded most of those graphic routines in assembly specifically tailored to that video chip.