that's done it! great thank you!
any idea what caused it?
I've been using avast for over about 10 months now after brief unsatisfying experiences with other av packages and i love it, that's the first problem I've ever had with it!
The speedy solution to this shows 1) why you should always post all the details of OS, Avast version etc. 2) make sure to check for updates regularly (it's easy to get complacent with the constant definitions updates) and 3) this board is great! If this had been the board for some other pieces of software all i'd have got was 'stfu d00d u must have done something wrong'