outlook express

Hi,
I'm running norton anti-virus on 95/98 client computers... Sometimes e-mail's contain viruses.
In outlook express when a 95/98 computer clicks on a new incomming message, it could activate a virus.Some of the computers use outlook version 5or 6. Is it possible to deactivate viewing it when you click on it.I know when they double click it, it opens a new window thats okay. It's when they just click on it and view it on the lower pane of the screen I would like to deactivate. Any help would be appreciated...