Some users of Windows Vista may have sound problems, along with an unknown hardware item in the Device Manager called "Multimedia Audio Controller". This means that you do not have Vista compatible drivers for you sound card, causing audio problems.
Solving this problem should be easy, assuming you know which sound card you have or have the driver disk.
If you have a driver CD that came with your computer or sound card when you bought it, insert this to install the latest drivers.
If you no longer have the CD, or the drivers are too old you will need to download the latest sound card software from the manufacturers website.
To simplify your search, many of the major sound card drivers for each company are located on the following websites: