PCI Express card?

Hi there,
 
I don't know if anyone will be able to be helpful, but since I've gottem a lot of uselful advice here before; I thought I'd give it a shot.
 
I recently bought an HP Pavilion Slimline (model S5570T) desktop.  I've installed Sonar 7 on it.  I wanted to replace the stock sound card with one of better quality.  In a compact computer like this, I get one expansion slot...a PCI Express slot.  I had bought an Asus Xonar DX card, but then found that it requires an additional connection to the power supply.  However, there is no unused connector to make use of.  HP Tech support toild me that in this model of computer, it should work without a power connection.  But after installing the driver software and getting no p[lay back or any audio from my computer at all; I found this not to be the case.  I set the default audio out as the asus card, but when I open Sonar 7, it gives an error message that the sound card is not recognized. 
 
Does anyone have any suggestions of a PCI Express card that doesn't require an available power connection, or do they all require one?  If so, what would be a good alternative to that (perhaps an external unit), since I only have the opne expansion slot to work with.
 
Thanks for your time!

I haven't noticed a lot of PCI-e cards out there.  Everyone seems to be going USB or Firewire. 

E-mu has one.  I don't think it needs an extra power connection, but I haven't verified this.  I have the PCI model and it's been a very good card.  Because of it's flexibility, the setup software can be a little confusing as you start out.  Once you've learned it, the software is very powerful. 

http://www.emu.com/produc...=491&product=19169

Good luck on your quest. 

Thanks Beagle.  It will be good to know if I decide to upgrade some day.