Install XAMPP and then make sure that you have both Apache and MySql modules running.
Then go to http://zen-cart.com/ to download the latest version of Zen Cart.
Extract the Zip file using Winrar or Winzip
Rename the extracted folder zen-cart-v1.5.1-full-fileset-09182012 to shop/catalog and then copy the folder to C:/XAMPP/htdocs folder
Then type http://localhost/phpmyadmin in your browser and click on Databases and then type the name of the database you want to create for your zen cart installation.
By now you have created a database for your zen cart installation, username for this database in xampp by default is root and password is blank.
Now navigate to http://localhost/shop in your browser and you will see the following page
Simply click on "Click here" to begin installation and on the next page click Continue.
Accept the license agreement by choosing the radio button " I have read and agree to abide by the Terms and Conditions as stated above."
On the next page scroll down and at the bottom click Install.
On the next page it will ask you to provide the database information. Database host will be localhost, database username will be root, password will be blank and for the database name, enter the name of the database that you created and then click Save Database Settings.
On the next page click Save System settings at the bottom.
Now you will come to the Store Setup page, here enter the name of the store, store owner, store owner email, country, zone, address and click Yes if you want to install the demo categories/products and then click Save Store Settings
Finally the admin setup, enter administrator username, password, confirm password and email and then click Save Admin Settings
You have now installed Zen Cart on your local server. Delete the zc_install folder inside the shop folder and also rename your admin folder to a secret admin folder name.