In IE, you can revoke safe for scripting, but the control is still called and you receive a prompt. You can choose to run or not run the control.

To prevent the control from being called, you can set the Kill Bit.

Use Regedt32 to navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\<CLSID of the ActiveX control>

and set the Compatibility Flags data value, using the Hexadecimal Radix, to 400.

Unfortuneatly, I know of no way to identify the ActiveX Control, other than removing all the entries, and installing the ones that you want to disable.