Thank you for the suggestion. I had tried that already with no improvement.
POSSIBLE SOLUTION: If anyone else is having this issue...Since my last post, I have re-installed the XP drivers
for the display. I have limited resolution options but at least the screen has been clear.
...Also a point of interest about this glitch is that 1024x768 works well using the XP drivers...but does not fit the screen properly and stretches the text/images (in addition to the artifacts) when I was using the Windows 7 drivers. I played with the stretching screen options with no joy.
all sorted now, though! good ol' XP!