I have an XPS 400. It will not power up, and I have the flashing amber light on the start button. If I take out the battery and plug the computer back in, the fan will start for about 1 second. There is a green light on the mb. Otherwise, the computer is dead. I have checked all connections and have replaced the battery. Thank you for your help.
I have the same problem. Did you figure out what it was. my friends tell me it is probably power supply.