speech recognition/ sound card

I have an XPS M330.  The other day I tried to activate the speech recognition program. I received a message stating:

The wizard could not start.

Make sure your audio hardware is working properly

and check your audio configuration in the Audio Devices and Sound Themes control panel.

This same message now appears every time I turn the computer on.

Apart from the fact that I cannot turn on the speech recognition program, I have been having lots of trouble, since then, with the speakers and microphone.

I lost the microphone when I was in the middle of a skype conversation.

The microphone was mysteriously reactivated later.

When I go to the "controll panel" and adjust the microphone levels I am not able to fix the adjustment because the "apply" button is greyed out.

I have downloaded new drivers for the audio functions but I am not sure that they have remained uncorrupted.

Please help me to fix the microphone device, the sound system generally, and the inbuilt speech recognition system.