Thanks to all for prompt reponse.
I would only be online for as long as it would take to download avast! and I would not be doing anything else.
However, I think I'm being a bit thick. If there is no, or very little, threat in the scenario I set, then why do we need ant-virus software? I know there is a definite need for it, but I don't really understand why the threat is low during the period(albeit short) before installing avast! after having uninstalled AVG. I'm not doubting the responses I have had. I'm just not clear how it all works.
Again, thanks for all the help. Much appreciated. Any added clarity would be great.
Best Regards,
Bobbler