Here we go...
1*Download the Latest Driver for X-fi, for XP or Vista, that it's up to what OS you use.
2*Get some work to your compression utility (7-Zip, WinRAR, etc) and extract the driver to a folder.
3*Now go to the extrated folder and enter the "Drivers" folder, run setup, wait (Remember to reboot)
4*Done, lol
P.S.: It should work not only on Audigy 4 but on Aufigy 2 series too, for Audigy only cards i don't know, sorry
Remember that you do this at your own risk (i haven't found problems, if you found just uninstall the drivers and install the original ones and all sould be fine
Now i'm asking myself, the X-fi wasn't made from "nothing", well i think Creative say X-Fi isn't an "upgrade" from Audigy series... if so why the drivers work? lol
BCool
Edit: Word corrected
