If you are doing this for yourself (you have access to the computer where you will install the ocx) the you use the command line or "run" dialog to register an ocx. HOWEVER, there are often support files that might be needed as well, and therefore simply registering the ocx might not be enough.
Assuming you only need to register the ocx, that is done with at the command line like this:
regsvr32 "C:\Path Here\gif.dll"
The more robust way to do this is to create a Setup program, with the package and deployment wizard, or with a thrid party tool such as Wise or Install Shield.
Woody Z
http://www.learntoprogramnow.com