did u run the multiregion dvd patch on the slayers 2.5 disc (or any of the multi region dvd patches for the original ms dash)? If you did you cannot boot the dash with the original bios, becuase when you run the patch it makes your original ms dash unsigned and the original bios cannot run unsigned .xbe's. So if this was yoiur case, then just run the multiregion dvd patch again and it should solve your problem (running it again returns the dash to original condition). Hopefully this helps you. This was the problem i was having and it took me a while to figure out the problem (some people here also came to the same conclusions). Good luck.