Hi,
I don't know what OS you're running but I had the same problem under XP Home Edition after installing SP3. I right-clicked on the ATI TV shortcut, chose Compatibility Mode and chose Win 98/Me. This fixed the problem for me. Hope it fixes it for you.
One more thing: I got this to work in Windows Vista Home Premium by downloading and installing the Windows Vista 32 bit drivers from ATI. They are the ones for the 550 PCI under TV Tuners. I just installed them, installed
ONLY MMC 9.16. The first time you go into TV, if you want to resize the screen, do it manually, or you will get a BAD_POOL_CALLER error that will shutdown Vista.
Don't use compatibility mode with Vista, just install as Administrator.
Right-clock and choose Run as Administrator. I also have User Account Control turned OFF in Vista. I hate the prompts. Everything worked fine as long as I just resized the screen manually by dragging. You may have to reposition your screen 2 or 3 times to make it stick, but it eventually will . . .
Let me know if this helps anyone. Please post replies.
Mark
One more note about Vista: The only driver that will work with Vista without corrupting your display and causing a bluescreen is an older version: it's the most stable driver on XP or Vista. It's version 6.14.10.173. I also had good luck with MMC 9.13 with this driver in Vista. I wish ATI would patch this and make it available again for all of the AIW users. It would be so easy to fix. If you want a driver that will work on Windows 2000, only version 6-2_xp_t550_wdm_30152. (The .173 driver in on the original ATI 650 Pro install disk. Not sure if you can still find it at ATI/AMD previous drivers.)