Free anti-virus.  Normally I poo-poo such free products as they are usually just an inducement to buy a fuller product, that otherwise would not warrant customers' spending money.  However, an exception has come to light:
http://www.activevirusshield.com/antivirus/freeav/index.adp?  will lead you to a free copy of Kaspersky, one of the better rated products.  Normally the acronym 'AOL' would be enough to scare me off any product, but in this case there is no requirement to use AOL.  The only advice would be to use a disposable e-mail address for activation, and to decline the offer of the toolbar during installation.