Not the speakers

My computer is not playing any sounds from the internet or from any other source and I've tried using different speakers but its not working still and when I plug in my speakers it'll say they're not plugged in sometimes and when it is saying they're plugged in it won't send any sound to them except when I click test speakers then it plays the test tones perfectly and when I plug in my head phones it doesnt even show that they're plugged up. It says I have Realtek Digital output but I don't know what that is. So does anyone know a way to fix this