Thanks guys and special thanks to 33whatever for making me feel young and wanted again!

I managed to sort the thing out, but it was a bit of a nightmare and it involved me taking the sound card out, then putting it back in again, then going to the control panel, going to System, then Device Manager, the Hard Ware profiles followed by a handstand, two cartwheels and a flying kick...

...I'm sure you get the idea.

Anyway thanks for your help and all is well.