Loss of sound after a recent update on T500 -- Thinkpad General

[#1]

Symptoms

I keep my T500 current with new drivers, however in a recent update (I do not know which) I lost almost all the volume on my speakers and headphone.

Diagnosis

T500 series running Windows 7 64bits 

Solution

The problem can  solved with a full power reset of the laptop.

Shut it down and take out  the battery,probably  out overnight.

Plug in  the battery back, switch the laptop on and it and you must not be getting the sound level as usual.