> I want to download www.abcd.ab.cd/123.
> 
> 1. All addresses must contain 123. If it does not, I do 
not
> want to download it.
> 2. I do not want to download any files with extension xy
> 3. I do want to download all files with extension wz
> 
> How do I do it?> 
> (I have tried everything)
> 
> HTTrack is instead deciding to download www.abcd.ab.cd as 
well.
> 

Go to "Set Options"->"Scan Rules" and insert the following 
in the text box:

-*
+*123*
+*.wz

The first line rejects everything, but the second and third 
lines basically say "except this."  You shouldn't have to 
eliminate .xy explicitly, since that is done by the -* line.

I'm assuming that you use the WinHTTrack GUI.

Cheers.