Dear Boohbah & Hybrid,
Shortly after our last exchange, my computer started behaving really erratically, & I ended up having to have yet another fresh reinstall of Windows & everything else. I just got it back this week, so I wanted to reply & thank you again for all your suggestions--it was very much appreciated. This latest reinstall seems to have resolved a lot of the issues I described in this thread. I'm keeping my fingers crossed that my computer will continue to behave itself!
Thanks again, Regina
PS: Marking this thread as "Solved".