Note in order to install any certifcate there are 3 main steps:

1) Purchase SSL Certificate from SSLTree.com - click here to compare all certificates
2) Generate CSR (Certificate Signing Request) on your server

* it is very important that you generate the CSR from the server where you will be installing the certificate because the CSR contains your web server's Public Key

3) Install The SSL Certificate

Generate CSR for IIS 6 (Windows 2003)

Follow these instructions to generate a Private Key and CSR. You must have at least  Window 2003 Service Pack 1 installed.

1. Open the Internet Information Services (IIS) Manager. From the Start button select  Programs > Administrative Tools > Internet Information Services Manager.
    
2. In IIS Manager, double-click the local computer, and then double-click the Web Sites folder.
    
3. Right-click the Web site for which you want to request a certificate, and then click Properties. By default it will be Default Web Site, yours may be different.
   
   
    
4. Select the Directory Security tab and click Server Certificate in the Secure communications section.
    
5. Click Next in the Welcome to the Web Server Certificate Wizard window.
    
6. Select Create a new certificate, Click Next.
    
7. Select Prepare the request now, but send it later.
    
8. At the Name and Security Settings screen, fill in the friendly name field for the new certificate

   Tip: the friendly name can be any name that helps you remember what this certificate is for when you see it in a list later. We recommend using your domain as the friendly name, such as mysite.com.

9. Select bit length. We recommend using a 2048-bit length (2048 is required for EV SSL). Click Next.
    
10. Leave the 'Select cryptographic service provider (CSP) for this certificate' unchecked. Click Next.
     
11. You will be asked for several pieces of info which will be used by GeoTrust to create your new SSL certificate. These fields include the Common Name (aka domain, FQDN), organization, country, key bit length, etc. Use the CSR Legend in the right-hand column of this page to guide you when asked for this information. The following characters should not be used when typing in your CSR input: < > ~ ! @ # $ % ^ / \ ( ) ? , &
     
12. Enter your Organization (e.g., ABC Company Inc) and Organizational Unit (e.g., E-Commerce Sales). Click Next.
     
13. THIS IS THE MOST IMPORTANT STEP! Enter your site's Common Name. The Common Name is the fully-qualified-domain name for your web site or mail server. What ever your end-user will see in their browser's address bar is what you should put in here. Do not include http:// nor https://.  Click Next.
     
14. Enter your Geographical Information for Country, State, and City. Do not abbreviate States and Cities. Click Next.
     
15. In the Certificate Request File Name box enter the path and file name where you want to save your CSR. You can use the default of c:\certreq.txt. Remember where you save it, you'll need to be able to find this CSR file later. Click Next.
     
16. Review the data on the Request File Summary screen and click Next.
     
17. Click Finish to complete the Wizard.
     
18. Now, from a simple text editor such as Notepad (do not use Word), open the CSR file you just created at c:\certreq.txt (your path/filename may be different). You will need to copy-and-paste the contents of this file, including the top and bottom lines, into the Issue Certificate relevant box 

Submit your CSR to SSLTree.com by logging into your My Account dashboard and clicking Issue Now link and then copy and paste theCSR into the text box

Install the SSL Certificate for IIS 6 (Windows 2003)

SSLTree.com will send you the SSL certificate via email. Using a plain text editor such as Notepad, paste the content of the certificate:

You should then have a text file that looks like:
 
-----BEGIN CERTIFICATE-----
[encoded data]
-----END CERTIFICATE-----
 
Make sure you have 5 dashes to either side of the BEGIN CERTIFICATE and END CERTIFICATE and that no white space, extra line breaks or additional characters have been inadvertently added.
 
Save it with extension .txt.