hmmmm interesting... did you do any mods, like cut your case or a heatsink up recently?
that always creates a lot of metal dust, and that caused me the one or the other headache in the past heh

whenever you cut metal or even remove insulation from wires and cut them, do it far away from your pc!
if you remove insulation from a wire and cut them up to prepare for a mod, you always end up with small short pieces of wire that can ruin hardware real fast..