I seem to have managed to get Norton Internet Security 2006 beaten back sufficiently that it works without overwhelming my computer. I conclude that NIS/Norton Anti-Virus wasn't the culprit, but Norton SystemWorks. With NSW uninstalled, my hard drive no longer ticks at least every five seconds, for instance, and the machine will actually slow to an idle (I watched it do so on the performance monitor), which is okay with me. When my computer is doing nothing, I want it to do nothing, not keep pinging the hard drive doing who-knows-what. At least I know now to not touch NSW again, and to see if I can get a refund for that portion of the purchase. What a waste of resources!