I have a Windows XP SP3 MCE 2005 PC that uses a dual Hauppauge PVR-500 MCE dual tuner card setup and has worked flawlessly until a recent OS rebuild where I noticed the recording quality had become unusable. I’m not sure if I should be using older drivers or what but I can tell you that I have just about given up trying to get it to function correctly. These are not new tuner boards but they worked OK until the OS rebuild in April which was prompted by a hard drive failure. I have also successfully run MCE using a quad tuner setup without issues via registry changes for several years. As an aside, I attempted to upgrade this machine to Vista Premium and could never get the TV tuner functionality to work. The OS installed OK and Media Center would open and configure but as soon as I opened Live TV it would hang up. This box is a late 2006 ASUS M2NPV-VM motherboard with an AMD 4200 X2 processor and 2GB memory. Again, I built it originally in October 2006 and it ran perfectly until the HD failed and I rebuilt the OS with new drives.