have you tried taking the motherboard out of the case, and hooking it all up, it could be a short caused by a design, or misplaced motherboard riser. it could also be you are overclocking. ram , or the settings for the ram. do you know if you have updated anything right before the problem starts, do you have a easy bios auto updater? any other auto updaters?
Surface Pro 5 News - release date, UK price, features, specs