My ‘56 Chevy

I'm posting on behalf of a friend. Basically they're not that technical, and now all of a sudden the Windows Defragmenter tool won't run anymore. It has an error message that says 'Disk defragmenter could not start'.

The amount of space on the hard drive isn't the issue. Also he's tried this, this, this, and he's also tried it all in Safe Mode, yet nothing.

Does anyone here have any other ideas?

Thanks