How To Install Joomla 2.5
1) Download Joomla 2.5 from joomla.org
2) Create a new folder in wamp directory or web server
3) Copy and Paste Joomla 2.5 zip files inside folder
4) Extract file
5) Go to the url like http://localhost/joomla or example.com
6) Install the cms
7) Select Language >Next >Next >Next
8) Select database Type(Mysql or Mysqli), username, password, Database Name, Table Prefix(unique is always better). On a wamp server, the settings are mysql, localhost, root, 'no password', 'Any name like Joomla for the Database Name', 'Any name like Joomlacms for the Table Prefix'
9) Select Next >wait while database setup takes place
10) Select Next
11) Add Site name, Your Email, Admin Username, Admin Password and Confirm Password. You have the option to install sample data.It can be helpful to learn the cms.
12) Select Next
13) remove Installation folder or rename it.
14) Open website and you should see the home page.
15) You can access administrator here:
http://localhost/joomla/administrator/ or example.com/joomla
Your username and password is what you had previously entered during installation.