Many thanks to all three of you guys.
I think I've got things back under control here.
I have downloaded/installed CodeStuff Starter. Very helpful. I found a few unnecessary items and turned them off.
I also raise the priority of MC as suggested.
I also found deep in my Boookmarks a web site I had visited a while back. This is: musicxp.net/. They have a list of 28 well-explained recommendations for XP settings that enhance all things musical in XP. This unfortunately includes visual changes that make XP look like Windows 98 all over again. But I can deal with that--just close my eyes and listen to the music.
Since making these changes I haven't heard a single pop, click or hiccup in MC playback even taking actions that max out the CPU into a plateau peak at the top of the graph in TM.
I'm a happy listener once again.
BTW--escaflo--I think the musicxp.net suggestion on the PIO/DMA issue is contrary to your advice. They suggest favoring DMA over PIO in that setting. You might want to check it out.
Again, thanks to you all for the helpful responses.
Regards...