You know, some formats (txt, gif etc.) will be shown on the browser rather than downloading when we try. Below is the script which will help you to download any file.

 
        Response.Clear();
        Response.AddHeader(“Content-disposition”, “attachment; filename=<filename>”);
        Response.WriteFile(“C:\</filename><filename>”);
        Response.End();
</filename>

The same logic is used in any server language.

ELMAH (Error Logging Modules and Handlers) is an application-wide error logging facility that is completely pluggable. It can be dynamically added to a running ASP.NET web application, or even all ASP.NET web applications on a machine, without any need for re-compilation or re-deployment.


Check these resources: http://code.google.com/p/elmah/

http://msdn2.microsoft.com/en-us/library/aa479332.aspx