Thanks for that Info, RNfromTN.
According to that, my computer is fine as far as the Windows XP SP2 criteria.
What is NOT out of the question that could be causing a failure to communicate between my computer and avast is my OLD Hardware. Maybe as more changes are made to avast ... maybe it no longer works well with REALLY old Hardware like my computer.
I say this because a very similar situation happened to me years ago when I used to have McAfee on my Gateway computer with Windows 98SE. It used to work fine for a couple of years. Suddenly one day I just up and encountered a failure to Boot Up.
Long story short ... 3 Windows Reinstalls later, I had confirmed that for some reason, McAfee no longer worked with my computer. McAfee was now for some reason causing my computer NOT to Boot Up even fresh after Windows Reinstalls.
So, I had no choice, but to stop using McAfee.
So, that's why even though avast has served me VERY well since I believe 2008, I don't rule out that MAYBE it might no longer play well with my old computer. But, the Smoking Gun is NOT yet on the table. At this point, it's just the theory I'm studying as per the fact that today my computer has worked fine ALL day ... after giving me fits the past several days.