Further to Nick's insistence on the "silent" Trojans - he's right. For the past couple of days, as a result of an unrelated but unexpected event on my computer, I've been engaged in a cleaning exercise. I have pretty solid AV and, I thought, pretty solid anti-Trojan software on my machine. But, becoming suspicious, I loaded a new Trojan remover. Lo and behold, it pulled out 46 infection sites. I was, to say the least, a tad surprised.
So, Nick's warning is perfectly correct - these things can sit on your machine completely without a clue being given to you. I spent yesterday changing passwords!
Mike