Blue pixles all over my screen

try changing the hdmi cable, if that does not work then could be hardware issue which would need to be booked in to repair, is the xbox under warranty still, if not check your country for sales of goods laws as uk covers item up to 6 years IF a manufacturing fault and not physical damage, EU has simular laws too.

That sucks. Based on your comments your box is bad. Call support to get a new one or if purchased recent from local retailer an exchange perhaps.

Try using another HDMI cable to connect to your TV. Also, try switching ports to see if that helps. Be sure to note that if you are plugging your HDMI cable straight from your Xbox One console to your TV, that you are firmly plugging into the HDMI Out port
on your console to one of the HDMI In ports on your HDTV. If you find out that the issue is either a faulty HDMI cable or your console itself, you can contact Xbox Customer Support at 1-800-4MY-XBOX, let an Xbox One Hardware Agent know about your issue, and
request for the Advanced Exchange Program for a fulfillment for a new HDMI cable or for a new console! Good luck!

Ok now it won't even turn on

Thanks to everyone for your responses. To anyone else having this problem ......GPU failure. Exchanged for XBone # 2 at game stop today. If your box will not turn on like mine (with game inside) push power+eject until it comes out. I was able to get my
game out. Game stop said that if you cannot get the game you either wait for Microsoft to exchange (3/4 weeks) of take it on the chin for the game. But like I said me and the game stop guy were able to eject the disc after a few minutes of button pushing.