In this article i'm going to show you how to set the Ajax captcha plugin with AUser Manager on a Joomla site, in other words, how to set captcha on register new user form, in the same way these reading is usefull for set Captcha on login form or on reset password form or on remember password form. We assume that you have downloaded and installed the latest version of AUser Manager on Joomla 1.5.X, so now we need to check that all components and plugins settings are proper configured. First of all check that the Ajax Captcha plugin is enabled then let's go to set the captcha plugin parameters,in this example we are going to set the easy math captcha option, as you can notice yourself there are several other captcha type like: the classic image with letter with the audio in mp3 for accessibilty, the roman number, and the ASCII art.The other parameters are not necessary for the captcha type choosed "easy math" and are simply ignored except for the last failed attempts, this is an important parameter, it means after how many failed attempts you'll block the form submission, pay attention to set this value. Now let's check the component AUser Manager parameters, on the component toolbar you'll see the parameters button click on it and you'll see all the component parameters. We are interested on captcha option, more deep, we need to set on wich form we want protect with captcha, the forms are: login, registration, reset, remember passaword, so simply enable the captcha on your desidered form, in this example we have setted the captcha on all form, but you can depending on your needs set only in the "create new account". With these setting you are able to configure the AUser manager form for use or not the Ajax Captcha plugin in the various form like registration,login remember and reset password accordingly with your site needs.