[Dalberg-Acton]

I let it update every time. When it won’t paste, I open Notepad and I can paste the text into it, but not Firefox.

[Viking2002]

Try running the Windows AIO repair tool and give it a thorough sweep. Could be a weird registry error or any number of other causes. Sounds like it's gone on too long for a system restore to work. Does it happen in any other browser?