You have probably clicked on a mailto: web link which directs links to send e-mail messages to wherever the webmaster chooses. Go to the View menu -> Show Statusbar if it available, and then make sure the bottom of your screen is visible. When you hover over a link, if it says: mailto: it will open in your default e-mail reading application set by your browser or your e-mail program preferences.
Apple menu -> System Preferences -> Software Update lets you change how often you see the software update window.
G5s are not Intels.