Windows 10: how to prevent a new notepad window from opening when the file is open

This is an annoying thing to me. After I open a text file using notepad, when I double-click the text file, another notepad instance opens the file. I can edit the file at both instances making a synch problem. (Sometimes I forget that file is already open which has not been saved, and re-open it and edit and save, destroying all the changes I made in the first notepad window.) Does anybody know how to fix this behavior of notepad? I want the existing notepad to be activated when I open the file again when it's already open. Thanks!
*Mad

:)

 

.bin files opening up in notepad

So good news and bad news, i was fiddling around with it and saw that the keys with the things that made bin files open in notepad were back but the user choice thing wasnt when i deleted them again and restarted bin files still opened in notepad. So i
know that they open in notepad because the files a and b keep coming back but i dont know how to get rid of them.

 

opening an old document from windows 7 to windows 10 on a new computer

When the file opened in Notepad, was it readable? If yes, then it is NOT a Word document!

Or did it open in WORDPAD, a different program from NotePad? That would suggest that Office has not been installed on the new computer.

 

Mine opens as it should and cannot get it to do what yours is doing