Okay...so, I reformatted my hard drive and reinstalled XP Media Center onto my computer. At first, the onboard sound, RealTek HD Audio Driver loaded on the first reinstall of Windows I did...but after that (I've reloaded Windows multiple times to try to rid myself of the nuisance), it's never loaded. I've left it reinstalling that HD Audio Driver over night a couple times. Well...yesterday, my wife saw the message, "Microsoft Bus driver should be loaded in your system before installing Realtek HD Audio Driver!" I went online and found out that if that happens, I have to reinstall the original chipset driver and motherboard driver from your computer manufacturer's support website, so I did that. But, I cannot get my new Soundblaster X-Fi soundcard to work at all! I've installed those drivers multiple times now to no avail. Anyone ever had anything like this before??
Also, since I reinstalled all the original chipset drivers and all, should I go back and reinstall Windows one final time to get a good, clean reinstall of all the original manufacture's programs and sound drivers and such? Or just leave it and try something else?

Disable the onboard sound controller. Yellow_Flash_Colorz_PDT_17

In the BIOS settings, right? I already did that. It already was disabled, so I enabled it again, restarted the computer and then disabled it, just to be sure. Or is there somewhere else you have to disable it at?

I have the same card you have. I uninstalled my Realtek audio and installed my X-fi drivers and it works like a champ. Since you're not using your motherboard for sound, you don't need any audio drivers installed for it.

When I get home, I'll just uninstall all the X-Fi drivers and components and reinstall them again, see if that works. If not, I'm completely f*cking clueless.

Alright...I figured out half the problem. It might help to actually use the jacks for the NEW card instead of using the jacks for the onboard card.
But, still...no workie. Now, it gives me this error message when I try to use it: "There is no supported audio device available. You need to close the application. Click OK to close the application now."
I'll keep plugging away at it, I guess....

And you have uninstalled your Realtek drivers?

Yeah, everytime I click into "Add/Remove Programs", I check to make sure that nothing else in installed.
EDIT: Nevermind. Apparently I didn't run the Windows Update after the last reinstall of Windows that I did. I updated to the latest WMD driver? Or something like that, and now, it magically works. So yeah....I must've ran the update after my last reinstall, and thought I ran it after this reinstall. Let this be a lesson: DON'T BE A DUMBASS LIKE ME! RUN ALL THE UPDATE PROGRAMS BEFORE ASKING QUESTIONS!

You need to run Windows Update 4 or 5 times to get all the updating done.