Hrm... well... without any ranks in the mechanics skills it's considered untrained, which would mean you are already pretty clueless... but I mean, if you really want to go the extra mile... I'll go with Reiji's layed out flaw. 10BP and you can take an Incompetent for a skill group but may choose a single skill in the group which is immune... call it "Idiot Savant" and there you go. :)