I bought an HP HTPC a year ago from an online retailer. It's an older model but I bought it as new. Our family loves it, we run Windows Media Center XP on it and we've been very happy with it. Long story short, it's a highly specific build by HP and the video card burned out so I was able to get a Nvidia Geforce that worked in the computer. It installed and works great but as soon as I install it the onboard audio stops working in what appears to be an IRQ conflict. There are not other PCI slots to try, there are no options in the bios to modifiy the IRQ numbers. I tried to turn the comp back to the non-ACPI mode but I still can't modify the IRQ numbers. The computer is an HP z558 HTPC and I've installed, and updated, and uninstalled all associated hardware, programs etc, in and any number of combinations to try and get the audio and video to work. Thanks for any assistance in advance!! I've been dealing with this for a month and I'm at my witts end.