I have Windows 7 which is similar to Vista and there a number of places to find this out.
If I select on the Orb bottom left, then on the menu select "Computer" it opens up a window. One of the options on this windows is System Properties.
Or if you select on the Orb and when the large menu is displayed type "System" in the search field at the bottom. This displays a list of options with System in them, and one of them should be System Information.
As I say, this is on windows 7 so Vista may be slightly different so you may have vary my instruction slightly.