Thank you @corradoventu and @tea-for-one . I decided to skip 24.10 and install 25.04 alongside Win10 and 24.04LTS. 24.04 is using about 160 GB of a 600 GB partition, so there’s plenty of room to divide that. But I ran into a couple new problems that may be hardware related.
I downloaded Ubuntu Studio 25.04, verified it with SHA256SUM, and used ‘Startup Disk Creator’ to create a live USB on a new 32 GB flash drive.
Booting from the new USB took inordinately long (~12 minutes) and when the desktop finally showed up, there was a message indicating something went wrong and that I should try booting again. Tried again, using the other USB port (neither is on a hub), with the same result. Suspecting a faulty flash drive, I created another live USB on another (new) 32GB flash drive. This time, booting resulted in a blue screen system error, with options to run system tests. It took a couple tries, but I finally confirmed I could successfully boot to 24.04 LTS with no USB drive plugged in. I inserted the live USB into the other port and tried booting again, resulting in the same blue screen system error page.
I’m going to give it a rest for now, and probably try again in a couple days. Even though the .ISO verified properly with SHA256SUM, I’ll download a fresh copy and try a different flash drive. If that still doesn’t work, I’ll put the project aside. The laptop is 10 years old. It’s possible that the USB controller may have a problem, and also, either the graphic chip or the screen is showing signs of potential failure (every couple hours the screen will start flashing between the desktop and a black screen for 15-20 seconds - happens in Win10 also). So I need to anticipate a new system anyway.
All for now. Thanks again.
-R