Computer speakers to record?

And while I always listen to my laptop music, now suddenly it did not work anymore, but after a long back and forth, but now I hear almost myself -> Echo? As if it would reflect my noises, say - extremely annoying!

Can anyone help me?
Google does not find anything really helpful with my description.

Deactivate microphone or set it so that you do not hear its input?

Thanks - to the simplest of course not thought ^^ :-D