Hi,  I wonder if anybody could help me out here; it might be the biggest mystery since even Apple warranty people couldn't say what was going on; my brand new imac, the biggest screen, the fastest processor keeps sending data at average 40 gig per second round the clock, non stop, no break; as a consequence household network slowed down to prehistoric levels and we're running out of the allowable downloads way too fast. The only external software that had been downloaded...