if i have dll library and header files how can i used it in borland c++>

Usually, you need a static library (.lib) for any DLLs you use in your program. Anyways, I don't know Borland, but here are the general steps for setting up a compiler to use an external library:

  1. Get a hold of the necessary files to use the library.
  2. Configure the compiler's library and header search paths to the location where you put the librariy's files.
  3. In the project you want to use the library in, look for "Libraries to link with" or something similar. Add the libraries here.
  4. In each source file that you need to use the library, include the necessary header files with
    #include <headerfile.h>

    Replacing headerfile.h of course, with the name of your header file. Also note that you should use quotes if you have the header file in the same directory as the project.

If you're having problems with these instructions, I probably won't be of much help, because as I already mentioned, I have never used Borland C++.