Hello MaryW,
If Windows will not update or upgrade to Windows 10, I suspect you have a failing hard disk drive or SSD.
Be sure you have a backup of your data before starting. Tap or click here to see how to perform a Refresh of Windows 8.1 without losing your programs or data.
If that process fails, then you most likely have a bad disk.
Support for Windows 8.1 will end on January 10, 2023