Did you not read anything on this entire page? No one here can exactly diagnose the issue unless they have the technical expertise to do so or is willing to help along with having the device within them.

Sounds like failing power supply. It doesn't turn on or will turn of after some time because the power supply can't keep up with the extra juice the Kinect sensor is using, If when you unplug the Kinect the Xbox stay on and doesn't cut off by itself anymore that lends hand to that being the issue. It also means as time goes on it will fail more until it quits working and fails completely.

My roommate bought a Xbox 1 S soon after release and let me use so we could play online together, after 6ish months maybe, It got to where after playing it sometime it would turn off by itself… Sometimes it would take multiple tries to get it to come on and stay on. Sometimes it would just come back on for another random amount of time. Over a short period of it doing this it continued to get worse and worse until eventually I had to end up spamming the power button, unplugging it, plugging it back in after a minute or so over and over until it would come on for another short period of time mostly. On occasion it would stay on for like 3,4,5,8 hours but was rare. I found pressing the disc eject would sometimes get it to come on and stay on.. there was a method I read to it but don’t remember it mostly. From my research my conclusion is the most likely issue is with power supply maybe, or a bad software update but I doubt it, We got replacement via warranty. Try contact a circuit board repairman and let them

When the Xbox One S was released my roommate bought one and let me use so we could play online together, after a couple months 6ish, It got to where after playing it for sometime then it would turn off by itself… Sometimes it would take multiple tries to get it to come on and stay on and sometimes it would just come back on for another random amount of time. Over a short period of it doing this it continued to get worse and worse until eventually I had to end up spamming the power button, unplugging it, plugging it back in after a minute or so over and over until it would come on for another short period of time mostly. On occasion it would stay on for like 3,4,5,8 hours but was rare. I found pressing the disc eject would sometimes get it to come on and stay on.. there was a method I read to it but don’t remember it mostly. From my research my conclusion is the most likely issue is with power supply maybe, or a bad software update but I doubt it, We got replacement via warranty, had no water damage. Sorry4You