Register/unregister my BHO using Delphi code

Just create the correct registry entries. Next time IE loads, it will load the BHO.

How?

Usign TRegistry, I KNOW you know how to do that.

Sorry to say but not :( I write app from hobby and not as a job.

What is the GUID (CLSID) you used for your BHO?

I don't see anything about my dll name. Where to specified where and what is my BHO dll.

And how to unregister?

Look, if you don't provide more info, how can I help you?
It has NOTHING to do with DLL names or anything.
It goes off the GUID.

Unregister is just remove the registry entry.

Now, you may be able to register/unregister your DLL using regsvr32, but I'm not sure.

the BHO is a dll that in my demo case is name IEhelper.dll, but I can name it test.dll. I wish to register this dll as every time when I run an IE instance to start my dll too.

For testing I use Register ActiveX Server from Delphi IDE. But wish to add it to install or at the first time running.

If I don't tell to registry to use my test.dll how can IE know what to use? I can have ten BHO in the same time for same IE instance.

As I said before, it doesn't matter WHAT you name it, it MUST have a GUID.
and you HAD to create a GUID for your DLL in order for it to be a BHO.

You can use the code I showed above to add it to the registry.

Maybe you need to readup on the registering of BHO's:
http://msdn.microsoft.com/library/en-us/dnwebgen/html/bho.asp?frame=true#bho_registration