Xi-Fii extreme
This may help some..I am running Wondows 7 64 bit.
I had the same problem with my X-fi Creative card and it took me awhile to get sound, but I did !
First I updated the drivers from the CD that came with the card, that got the card recognized, then I downloaded the latest drivers from Creative. But don't install with that !!!
Open it with an extraction tool such as Winrar and extract all the folders and files. One will be drivers. Then go back to Hardware Manager and upgrade your card drivers, pointing the source to the drivers folder which you have now extracted. Bingo !!
Sound now works perfectly and including the 5.1 is etc .