No sound when inputing notes w/ midi keyboard

I can enter the notes but no sound comes out. When i enter with the ouse or keyboard I can hear the note…why is this? I need the key oard to make sound so I can hear the notes I am entering

when I open up an old project it works, but only that old project. None of the other ones…If I make a new project from there it continues to work, but not if I start a new project without the old one being opened up first

I’m not sure what might be going on here. If you go to Play mode and click on the instrument track header for an instrument, you should now find that when you play on your MIDI keyboard, the notes are echoed back using the sound of the instrument you selected. Does that happen?