XP PC won't power down after installing HDTV wonder.

Dell Dimension 4550
XP SP2.
Radeon 9250 video card.
ATI HDTV wonder.

After installing the HDTVWonder card, my system will no longer power off.
Gets all the way to the blank blue screen with the cursor.
Cursor follows mouse, but it's hung there until I hold the power switch.
If I use device manager to uninstall the card, the system
shuts down properly. Upon reboot, XP finds the card, reinstalls
the drivers and the power problem returns.

Fix for this?
Thanks, mike