[Mrcy2u]

Located this registry change to disable HTC's built in Notifications Screen that tends to pop up during phone calls and occaisionally makes it dificult to get back to the keypad, etc..

You can stop the phone from loading the HTC Notification Manager by editing the registry:

HKLM\Services\NOTIFICATIONMANAGER\Flags
change the key from 0 to 4
and reboot

This will revert the phone back to Windows default alerts, to which you can disable audio and popup screen alerts.