Mixer Devices

When i click on volume control it says 'no mixer devices' or something along those lines. I dont know what this means but my sound worked fine yesterday and I think I was getting those errors then also but now for some reason sound has stopped working altogether. I don't know what to do I don't know if I need to reinstall my sound card or what?

Control Panel >> Administrative Tools >> service >> (Should Be Under)>> Windows Audio, Click it once and then in the top left it will was say *Start* click it, if you now have sound it was because you disabled the sound somehow.

Thanks you very much, its fixed now!