The air itself passing over the circuitry.. laden with dust, can form static charges.... not that its very likley anyway. also.. a vac is good to get the loose stuff up.. then you gotta clean it properly, best ways i know are air can or paint brush. The paint brush will last a lot longer i just had to strip my system, theres a lot of building work going on here.. new kitchen fitted, new bathroom. new dust i took my mobo out and took the fan off the top of my Zalman cooler, easier than taking the fan off the board as its a bolt on one. there was that much dust i eventually had to strip the whole lot off and clean it on a anti static foam mat on the floor... theres was just too much dust. Heres what i found: