Thanks for the reply. None of my video software is native 64bit, so like you, I doubt more memory would have any mesurable impact. I have the machine maxed out at 4 gig and rarely see memory usage go over 1.8 gig.
I've been exploring using Sandboxie to harden my current security, but I wonder if it is necessary. I currently run Avast 5.1.807 free, MBAM 1.5 free with weekly manual scans, and Windows 7 firewall. All automatic updates are on and I keep 3rd party apps up to date. Like you, I do have a pretty strong backup/image routine with Acronis disc image running a nightly incremential update. If I happen to catch the flu, I can always restore to a previous time rather than mess around with a cleanup.