Ok, I've used AVG Free,which isn't free anymore according to their website when I checked it a couple of weeks ago, and I've used MacAfee and I'm currently using Norton Antivirus.  I've not had any problems with Norton in the year plus I've had this laptop.  I spoke with the IT folks here at the university where I teach and there were as many opinions as there were techies but they all agreed on Ccleaner, AdAware, and that with the XPPro version of Windows if you had Norton when you bought the system it should work OK.

I found out the hard way that installing Norton AFTER the fact was a nightmare and ended up just buying a new hard drive.

A major problem I have is that I never have enough free space on the hard drive to run the defrag program that's built into Windows.  I didn't realize you have to give up 20%+ of your drive space if you want to keep it fresh and minty clean.

I would also like to know more about this mysterious firewall cache thingie...please?