When I left home this morning, all was well with the world...my Dell XPS400 was running smoothly, no indication of any problems. Came home this evening to find the PC basically lifeless, with only a blinking amber power light. No fans running, nothing. All attempts to revive failed. Disconnected power cord, cycled down, reconnected power.....nothing but that blinking amber power light. Does anyone know what would cause this? Power supply? something else? Thanks in advance.