Upgrade from Magento 1.7.0.2 to CE 1.9.0.1

Upgrade Roadmap for CE 1.9.0.1 from 1.7

1) take a backup of current database and current 1.7 code.
2) download latest magento from the 

http://www.magentocommerce.com/download
3) remove all folders and files from your 1.7 code (but you should 

have backup somewhere) and place all folders and files from the 1.9.
4) now from your 1.7 merge your following custom folders into the 1.9
    - Community app/code/community
    - Local app/code/local
    - Media 
    - your theme or package (app/design/frontend/default/<ur theme> or

 app/design/frontend/<your package>)
    - custom folders from Skin (both for adminhtml and frontend).
    - copy your custom xml files from app/etc/modules/ to current 

app/etc/modules/    - any custom admin theme folder 

from adminhtml/default/yourtheme.
    - copy your custom folders from adminhtml/default/default/ (1.7)

 to adminhtml/default/default/ (1.9).
    - custom js files if any from app/js/.
5) now go to app/etc/local.xml.Edit database details their.put your

 database username and password and database name.
6) now check the site.it done.