Well now, let me make sure I understand. When I bought the laptop, Windows Vista was installed and the purchaser is urged to make a copy of the (virgin) system - I did that. Then, over time, I make weekly / bi-weekly back-ups through the Windows back-up system. But I only keep the latest back-up of course. Now, as I understand it, these latter back-ups copy the data that I have generated, but not the core system - but what do i know..... In any event, i have both. And I must admit that an amateur like me can only guess about that last back-up being before the attack and no virus being present. But I can perhaps do a virus check of the data on the disc pior to using the disc? Have to travel for some three hours now - just letting you know so you don't think i'm not engaged in resolving this. As I said before, busy life with lots of travel. Thanks.