XPS 730 Sound Failure

I am running Vista SP2 32bit and my soundcard is a Creative Soundblaster X-Fi

2 days ago everything worked fine yesterday there was no sound. The sound worked perfectly before with no indication that the card might be at fault.

When I try the X-Fi shortcuts I get a window saying the current selected audio device is not supported by the application or, the audio device supported by this application is not detected.

The shortcuts affected are Console Launcher,Creative Diagnostics, Midi Player andTHX Setup Console every other Creative shortcut opens a window.

The volume mixer only shows SPDIF out and windows sounds.

The device manager displays both the Creative SB X-fi and Realtek HD audio both of which is says are working ok and have no conflicts there are no warning icons displayed against either of the devices.

I tried system restore to where the sound was working but that failed to restore it. When I try to play sounds volume level indicators on the mixer and media player suggest that sound signals are still being produced.

The only computer changes are some windows updates overnight between when it worked and when it didn't. These updates were security updates an Outlook update and the windows malicious security tool so nothing unusual.

So far the only advice I have found on line is reinstall / update the drivers, uninstall and reinstall the software and uninstall the software remove the sound card turn the PC back on without it refit the card and reinstall the software which I have yet to try

I have checked and nothing is muted I have also tried the headphone jack on the front of the pc just in case the rear jack had become faulty.

Any additional advice or information from someone who has already had theis problem would be of help especially any method of testing the card.

Also, any suggestions for a suitable replacement card for this pc if I am unable to solve the problem would be useful.

Don