When ever this has happend to mine it has had to go in for repair. Microsoft will email you a parcel label. (they have extended the warrenty to 3 years for this particular problem) I now have mine stood off the floor on little blocks with a desk fan blowing all around, I switch the fan on before and leave it running for 5 mintes after playing. Over heating is the normal cause of the problem so it may have nothing to do with your recent update. Hope you get it back before xmas.
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