window icon turn grey / no sound

hi friends

i am using Windows 7 64bit home premium on my dell studio 1558

facing something unusual....want to show
through 2 screen shots i am posting....

1st one is......my windows start button has turned grey
2nd is...........the window personalization side pane has turned dark

another thing is their is no sound in my laptop, even it shows all drivers
are installed and working properly