Xbox won`t power on

[schumy2001]

Hello,

it`s bin a while since I came here. My friend gave me his box yesterday saying the thinf won`t turn on anymore. I plugged it in yesterday to see for myself but the box just booted up fine. This morning I tested it once more and now the box is completely dead!!! I checked the power supply and poer button. They seemed fine. I also checked the CPU and that one lookes not fine. There is a dark somthing around the core. Could the CPU blow up? And if so why did the box turn on yesterday?

Sorry for my bad english I`m from holland