Wow! Many thanks for that, I'm just waiting on a reply from the people who make the Mobo to see if they've got anything helpful to say, and if that doesn't work we'll try your solution.
If possible I'd like to avoid a reformat, but if it's the only way, then it must be destiny.
I tried asking Creative Labs for help.
HAH!
They've asked me the same question for three days running.
It doesn't matter how I phrase, re-phrase, re-re-phrase the problem, they seem to think I'm sub-human and it's just a case of "Are you sure you've turned the power to the compuer on?"
Uh huh.....

Well, pending what Sapphire say, I'll let you know how I get on, as this problem seems to be amazingly common for those trying to upgrade from onboard sound. I've seen the same question in many different forums, but never a definitive answer.

Thanks again for your suggestions!