Photoshop Installation

Hi all.. would be grateful for your help.

For the last 3 days I have three times already installed Photoshop CS5 extended for which I bought a license.

All the times, after installation is "done" the application never starts, and when I click on the shortcut it tries to start installing again!

I've uninstalled and run clean up tool already twice.

What else please?

I have Windows vista.

Thanks!