If you have an older version of Picasa on your computer, it isn't necessary to uninstall it before installing Picasa 2.
In order to run Picasa 2, you must have Internet Explorer installed on your computer. While you don't have to make it your default browser or even use it, Internet Explorer must still be installed.
After installing Picasa 2, you can delete the installation program.
To get a head start on learning to use Picasa, click the Support link on Picasa's home page and then download the brief User Guide.
install Hello (optional) p. 6
If Hello doesn't download automatically, there is a link you can click to download it manually. The manual procedure is performed in the same manner as described for downloading and installing Picasa 2.