Actually, it didn't resolve itself and even got worse. I couldn't think of anything else that might have caused the problem except for installing the paid version of Ashampoo Burning Studio version 9.12. I ended up uninstalling Ashampoo, but it didn't seem to help. Would it make a difference that I also had Nero, a version that came with my new LG burner, also installed?
Finally, after uninstalling Ashampoo, I restored a TI image that was about a week old, which returned the computer to normal operation. I'm going to try reinstalling Ashampoo, after creating a new TI image, and see if it makes a difference.