That looks like a surface mount transistor or perhaps diode. Does it have three solder pads or two? Doesn't look like a capacitor or resistor, but it is pretty tiny.
If the laptop operates without it, that means it was either in parallel with something just like it, or was being used in a non-critical way. Sometimes when they are doing a BOM cost for motherboards they will use things like transistors as pull downs, diodes, etc that aren't strictly necessary for operation, but cheaper than supplying a different component in another parts reel.
If it was in parallel with something, that means whatever is left performing that function is under increased load. This could lead to premature failure.
A fire is not likely.
You probably could solder it back on if you have the right tools and a steady hand. Thermal soldering station, a magnifying glass or scope, and some fine tweezers.
I can't really pinpoint where it come from.