I have found my problem with my TV tuner card
I also have WD 74 10,000 rpm Sata hard drive as C: drive. And my Hauppauge WinTV PVR 350 Would not work. I reinstalled Windows on it using The Correct drivers from the mother board company Gigabyte. The drivers for my WD 74 10,000 rmp Sata hard drive, Which is (Silicone image 3112/3512 Sata Driver) At first I used The (Silicone image3112/3512 Raid Driver) And I was told to do that by Gigabyte and when I called up 2/17/2005 I was told to use the Sata driver not The Raid drivers. And on 2/17/2005 I reinstalled windows.
I do not know if this is your problem or not but it is somthing to think about.