My mother’s laptop has been running as fast as a turtle on a snail going uphill for a long time now. Everything has been done to it, including formatting it and installing another, less cumbersome OS, but nothing improves. I have an HHD available, I have done some tests and it does work.
Would changing the hard drive do any good?
Sectors that cannot be read reliably will get marked out, but I’ve seen plenty of HDDs that tested fine but still had obvious issues when reading data from certain areas. If your OS happens to be within that area then it becomes a problem very quickly, and you’ll probably lose data before the drive marks those sectors as bad.