My built-in microphone is not detected

[Guest]

I have a Toshiba Satellite a300 and it was originally with Win Vista.
A month ago I installed 32-bit Win 7 and the only thing that doesn't work is the mic! As you can see on the picture: http://tinypic.com/r/ie1jxi/6 there are 2 mics and the one that is the default is the headset one, which I am forced to use. The other one is "currently unavailable" and I think this is the built-in one! It sounds really stupid that the built-in mic is unavailable (it shows it even if the headset mic is unplugged.)
Please help me!! (

 

[Guest]

Yes, I read through a lot of the forums and I found people with the similar problem, that solved it with installing the sound driver! I downloaded and installed two drivers, but even with both installed, it still doesn't work! ((