That's the universal way to clean up roll back installs and other Windows update related.

If that's not working for you, there's probably a much larger issue at play on her machine and would be much better off backing up her data, wiping all the partitions and installing fresh. You'll likely reclaim more than 700 GB.

The only time I've seen situations like what you're describing is when these are machines that have been in use for years and have major Windows versions on top of major Windows version stacked on top of each other, not just incremental updates.