A website's security certificate gives users extended security by encrypting data between the user's browser and the Web server. Security certificates are installed on the server, so your website developers can securely transfer information such as financial or medical records. If you no longer need the certificate, you disable it by removing it from the website. This is accomplished in your Windows server Internet Information Services (IIS) manager.
Click the Windows "Start" button on your Web server. Click "Administrative Tools," then click "Internet Information Services (IIS) Manager."
Click your website name on the left side of the window. In the center "Details" pane, double click "Server Certificates."
Click your server certificate name. Click "Remove" in the right "Actions" pane. Click "Yes" on the confirmation window to confirm you want to remove the certificate.