Problems with sound in windows 7

First of all my problem isn't just about sounds but the sound problem is the biggest one.

I have a lenovo 3000 N200, I have installed windows 7 on it for about 9 months and it was working fine until a month ago. Suddenly the sound doesn't work at all, I first thought its a driver problem so I installed the latest one and still there is no sound, the device manager says that every thing is ok with the sound card yet there isn't any sound (I am sure the hardware is fine as I am able to play sounds on linux which I double boot with windows).When I play a song or anything Windows acts as if I'm not playing any sound , I checked sound levels every where possible and nothing is muted.

The second part problem is whenever I'm using windows and everything is ok (apart from the sound problem) and do a restart , the touchpad doesn't work and windows appears to be using the basic driver for graphics, and they don't work untill I do another restart (by work I mean I get the touchpad and graphics functionality again but still no sound!!).

Any help or pointers would be appreciated.

I tried it , but no lock. My problem isn't that I have low volume its that I don't have any volume at all, when I try to play a test tone I get an error that says that the tone couldn't be played I'm just confused whether its a driver problem or something else is interfering with the sound!

Here is a screen shot

does any one have a solution for this? I have to know before I solve it the hard way (install a fresh copy of windows)

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