I wanted to share my solution for a really annoying issue. One of those "this is why we love computers" moments. No real visible explanation, your stuff just ceases to function.
I have Windows 7 64-bit. I moved my X-Fi Elite Pro to a different PCI slot (to make room for a bigger video card), and then came the aforementioned trouble with the software. Sound was still working, but I couldn't get to Console Launcher to adjust the software controls (like headphone volume, EQ, et cetera). The error message reads "current selected audio device is not supported". Creative Audio Control Panel had also stopped working.
I was stumped for a while. What now? Dump my expensive X-Fi card + external module so I can install the video card?
This is what worked for me:
1) I tried several things, but in the end I decided to move the card back to the original PCI slot. Then I uninstalled everything Creative-related. (You may want to reinstall your software using the CD if you don't have the software installed at this point.)
2) Go to Programs in Control Panel and uninstall everything related to your sound card. Don't restart when asked to, otherwise this takes a long, long time.
3) Go to Device Manager and right click your sound card. Choose "Uninstall". If given the option to "delete drivers", check the box.
4) Delete the Creative folder in "Program Files (x86)" just to make sure.
5) Shut down computer, unplug cords and cables, move your card back to the desired PCI slot.
6) Reinstall your Creative software.
What I did was use the CD that says "'Drivers for Vista" (you don't get all the things like Volume Panel if you use only the downloads). In order to get the disc working with my Windows 7, I right clicked the Setup.exe and selected "Troubleshoot Compatibility". This opens a wizard with different phases, the important bit is choosing "the software worked in a previous version of Windows", then "Windows Vista" and then "Start Program". There should be no big problems. I don't use MediaSource or the other inessential stuff included, so I can't say anything about installing those.
Restart when asked to. Run AutoUpdate to update your drivers.
7) Done! Now try your Console Launcher. What seems to be the issue (or at least for me) is that the "name" of your device is apparently still reserved by the "ghost" of the card in its former PCI slot. Once you uninstall your software while in the old slot, that "ghost" is released.
I hope this helps many others with the same issue!