>>If you're not using a third part installer that offers support for self-registering .ocx files, bet one, and ditch the product you're using. You're asking for more trouble than its worth otherwise.
>
>Hi David, thank you for answering!
>
>Do you have any suggestions about a third party installer? (If so, where can I find it?)

There are several good ones on the market - InstallShield and Wise comes to mind. PC-Install has recently started doing Registry modification and shared .dll work, but I'm not sure how successfully. You can order them from most software suppliers - I don't know what's available where you are.

>>If you insist on doing otherwise, a call to REGSRV32.EXE *may* do the trick, depending on when it is called. The syntax is simply
>>
>>regsrv c:\windows\system\myocxfile.ocx
>
>Just don't know in which moment and how I could run this command automatically during the installation (I guess a post-executable written in Vfp wouldn't run because of Vfp5000.DLL...)

This program is not dependent on vfp500.dll being registered yet, but I *really* don't recommend this approach - use a third-party product built for this.

>>You can check search the Registry for references to your .ocx, simply by searching on the file name (it's the cheater's method, but it works). Make sure you make no changes to the Registry when you do this - otherwise your machine may become UNBOOTABLE.
>
>Taking this opportunity, which one is the registry file?

The Registry is not a single file - it is a set called hives. *DO NOT* attempt to open any of its components in any way other than using the Registry Editor - the contents will make no sense, and you are likely to toast your operating system.