Some programs, like MS excel, are installed in a server machine working as web server. Through client machine's browser I want to execute the server's programs like MS excel, i.e. MS excel will be shown inside the web browser of client. What will be code in ASP.NET, Javascript, VBScript or C#. At least where can I get the help of it.

I do not think this is possible with a Microsoft Office product, nor do I think that Microsoft licensing will allow such use of the product. What about integrating an existing web-based editor such as available from Google Docs?