Thank you for the answer, but for some reason it didn't work.
By the way I can say 2 things that might help you find the answer:
- This problem started after I installed HP solution center and other programs for HP printers.
- Before I asked this question I have found similiar problems in the forum. I downloaded the link that sombody replied (I didn't saw that it was for a different model) and a volume bar was apearing but it wasn't the original one. Now there just isn't a bar.