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.