Hello,
Sorry for the problem with running Notepad as an Administrator. While we don't officially support local operating systems such as Windows 10, I did search and find an article that may possibly resolve the issue for you. If you require assistance beyond the article, then you may need to speak with Microsoft support. Here's the article on running Notepad as an administrator in Windows 10.
If you have any further questions or comments, please let us know.
Regards,
Arnel C.