MuseScore won't respond to my keyboard unless in Enter Text mode

none of my keyboard keys will not produce any response on the system so where's the problem then?

What responsed to you expect anyhow?
What do you mean by keyboard, the computer keyboard or a MIDI device?

Please give us the precise series of steps you are following - which keys you are pressing in which order, what you expect them to do, what happens instead. Also try closing and restarting MuseScore, and then for example, try the following:

1) press Ctrl+N to create a new score - does that work?
2) finish going through the new score wizard, selecting the Treble template, all other settings at defaults
3) when the score appears, click an empty spot in the first measure once to highlight it
4) press N - does the note input cursor appear?
5) press C - does a note appear?

And if you click somewhere, make sure your mouse doesn't make double-click automatically. (obsolete mouses sometimes do that)
This puts the software in edit mode. You can get rid of it by pressing "esc" key on your keybard.

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