My system is Windows XP with service pack 1. AVG free edition (manual updates and scanning). Zone alarm free (online access granted to only recognised programs). I have frequently noticed my processor working hard without apparent reason.. The circumstances would be - I will be online (dial-up connection) with my monitor on standby. I move my mouse and inevitably the processor activity will return to normal just before my monitor screen is visible. I am extremely cautious about Trojans and viruses (having had much experience of). I would be very interested to hear any suggestions as to reasons why my processor would behave in this way. My suspicion is that it may be responding to external stimuli.