I have downloaded the Captcha control files (ASP.NET 2.0 source files - 27.2 Kb) created by Jeff Atwood from http://www.codeproject.com/KB/custom-controls/CaptchaControl.aspx, and been trying to add this Captcha control in the Toolbox in my Visual Web Developer 2010 since two days ago with no success. According to the instruction on how to add it from other sites, there should be a .dll file in the downloaded file, but I couldn't find one. Could anyone give me some advice please? Thanks.