Santa Cruz Installation Problems

Hello. I recently got a Turtle Beach Santa Cruz off ebay in order to replace the onboard sound of my motherboard whch had gone dead. However, I haven't been able to install it. I'm running Windows XP Pro SP3. I downloaded the latest drivers off the TB website (4193) and follow the exact instructions given in their FAQ for installation, however, after I accept the install of unsigned drivers, Windows always throws a "installed device error" and the installation hangs; if I end the instllation process I get a runtime error message. If I reboot the PC, I getno sound and the sound card is not recognized. Even if I uninstall the components, I have to manually remove the card and reinsrt it in order to get Windows to recogniz it again (I don't do this with the PC on, of course). Already tried changing PCI slots and no luck. I'm certain the PCI works becuase I had a SB installed in the very same slot (which was migrated to a newer PC). I'm thinking of doing a clean Windows install to see if it fixes the issues I've been having, but first I wanted to ask for advice here.
Here's more detailed specs pf the PC in question:

AMD Athlon 64 3500+ AM2
Biostar GeForce 6100 AM2 Mobo
2GB DDR2-667 RAM
GeForce 7300 GT 256MB
320GB Caviar Blue HDD

Thanks for your time, and I'd appreciate the help.