My sound has suddenly stopped can you help?

[GeoffB12345]

Hello,
When trying to play i tunes or CDs there is no sound - it has only recently stopped. I have noticed that in Device Manager - sounds and Audio device properties under Audio tab - the sound playback default device tab states "No playback devise" and it is greyed out so it cannot be changed or other options selected.
The Sound Recording tab has "SoundMaxXDigitalAudio"

How can I change the audio sound playback tab to

 

[treefrog07]

Try re-installing the SoundMax driver/software.

 

[GeoffB12345]

Try re-installing the SoundMax driver/software.

I don't have the disc - any idea where I can download it?