> But recently I started downloading a website whihc had 
> drop down menu in its form, from where we select the 
> products and go to the page describing that select 
product.
> But I was not able to download it. The mainpage gets 
> downloaded, but if I click on drop down menus and submit 
> the form it goes online to that particular website.

This is most probably javascript problem - complex 
javascript is very hard to handle, and sometimes httrack 
fails to parse it, causing broken links and missing files.
There is no solution for these sites, unfortunately - the 
embedded code is just too complex to analyse