Thanks for your answer.
I dont think thats the reason.
When i,ve made the update it was still in demo mode.After the update was made,the version of avst!4 home changed to avast!4 pro demo automatically without asking for it.After this update,these options altered themselves immadtiatley.
I have noticed too that this AV program was taking some time to respond now.This happened in a new formatted windows xp.and the first software installed.
So not to take any more risk to safeguard the pc from maybe future crashes i,ve chenged the AV software to another one.But in future i will try it again,and i will still recomend it.
Thanks again for providing it for free.