I'm happy to report that I found the source of the instability that my poor desktop was suffering from. It was Norton's Anti-Virus. My system routinely crashed if I let it idle long enough. I tried a number of tricks advised by some of the generous tech people who can be located in various forums on the net. Nothing worked.
Then my subscription to NAV ran out. Nice nice! I uninstalled Norton's, and voila! No more blue screens!
I'm now running Trend Micro's PC-cillin. No complaints so far. One of the big bonuses, aside from system stability, is that it doesn't use up nearly as many resources when doing a scan as NAV did. Norton's was slow!
