Lost sound in 15.10 few days after installing it on Lenovo T60

Output volume in Sound Preferences window is in the highest setting, and the sound icon on my bar indicates so, yet I no longer have sound. I installed Ubuntu Mate 15.10 a month ago on my Lenovo T60 and last week I lost all sound. When I boot into Windows 7 I do have sound.

Hi @yacinkov,

have you done a full system update?: