Skipy

Guy A claims that I must not leave my computer turned on overnight, as a friend of his did that one time and his house burnt down because of it. Question: If I leave my computer on for days and days, can it cause a fire at some point, and if so, under what circumstances? Take into consideration even the extremes, but also note that there is no living being next to it at any time. I'm not an expert in electronics but my common sense and the years of leaving my computer on 24/7 without any misshaps makes me think such thing is at most as possible as a meteor hitting the earth. Thanks in advance