You need a new licence if you're upgrading from Pro to another Pro tier - like Pro for Workstations and you will need a volume licence if you;'re upgrading from Pro to Education/Enterprise or to Enterprise LTSC 2024.
On a related aspect, people are familiar with OneNote. But if you are still learning, it isn't enough. Two tools help you make sense of your data:
The first is Zettelkasten. As you assemble a group of notes, you see the connections that arise out of them. The German sociologist Nicholas Luhmann...
No. You will have to do a clean install. If you want to go to 26H2, you'll have to wait til the fall, download the iso. and install it. Its a lesson: pay attention to what you're doing before making a mistake you can't do undo later.
If the files are corrupted, the only thing left to do is a clean install. Windows will not migrate files too damaged for an upgraded OS. Don't fight it. Hopefully, you backed up your data, personal files and drivers. Good luck.