Won't power on, only green dot

Hello guys, first of all sorry if I created a thread in a wrong section.

I have this strange problem. I have a xbox 360 slim rgh, everything was working great. A few days ago I bought a not working kinect, I repaired it, and when connected it to xbox I accidentally shorted kinect's 12V and ground wires, on xbox's AUX connector. Then xbox shut down, I restarted power supply. And xbox started, fan is working, green dot is on, Coolrunner red light is on, green led is blinking in 5 seconds rate. I measured the voltage on kinect connector, 12V and 5V are present.

I tried replacing the hdmi cable, connecting it to another monitor, tried using AV cable, nothing helps.

I am out of ideas, maybe someone have any? Looking for any advice, thanks in advance.