Un-installing Picasa
Picasa can be un-installed using these steps:
Close Picasa 2 by choosing File>Exit
From the Windows Start menu, choose "Start>Program Files>Picasa2>Un-install"
Click through each screen to continue the un-install process
If you plan to reinstall Picasa, you may want to leave your Picasa database behind (this way, you will not have to scan all your folders again). If you want to remove Picasa from your computer entirely, or you want to start over with a fresh install, remove the database.