If you have a valid subscription to Symantec Norton Internet Security, you can upgrade to the latest and greatest 2010 release for free.
If the link doesn't work, click on Trialware in the column on the left of the Symantec website.
Register for a free trial and download Norton Internet Security 2010. When you install it, enter the key for your older version and you'll find it works with this realease so that you have the latest, greatest protection for the remainder of your subscription.
For those of you who haven't tried Norton Internet Security for a couple of years, just register for the free trial and you'll be pleasantly surprised. It is no longer the bloated performance sapping can of rancid treacle that it was before the 2009 version. I used to hate it, but I'm pleased to be able to recommend it to family and friends now that it is so vastly improved.