Have recently had problems after computer freezing, when restarted, the
colours had gone and the writing very large, I re-installed the video drivers
and all ok however now my speaker icon has disappeared from the taskbar- when
you look at sound it says that the drivers are enabled but inactive ue to an
unknown problem.

Any ideas on how I can restore my sound?

The volume slider is at low but is grey and it won't allow me to slide.