Is there any good free anti virus software out ther for my computer illiterate parents? They have an old machine and little memory. (the machine that is, not them!)

AVG 6 is available from http://www.grisoft.com/ It is the most popular and widely used free antivirus program and should do a good job for them. It also uses very little resourves. Just make sure their email security settings and preview pane are set up correctly. Did you get and set them up with a firewall(Sygate/Kerio)? Take care and all the best!

Will it tell me how to configure their e mail security settings and preview pane? Since using virgin.net they hve been unable to get rid of the preview pane , risky for some viruses i know.

The preview pane setting is in Outlook Express>View>Layout. If they are using Virgin.Net, and it uses its own mail server and not Outlook Express or if you can get hem yo use another email service like Yahoo, Hotmail, Eudora they would be protected by the spam/virus filters that these services have built in. If you can have them stop using Outlook/Outlook Express for their email account is one of the best ways to prevent them from getting a virus.

i used preview pane in outlook. is it bad? how?

www.freeav.com

Most user friendly. Even your parents could update it :)