Internet Explorer - upper right hand corner, the little wheel looking button. Click it and go to internet options.

Firefox - upper right hand corner button with three horizontal lines. Click it, click options, click the general tab.

Google Chrome - upper right hand corner, click the button with three horizontal lines. Click settings, check the bullet that says "open a specific page or set of pages" (located under "On Startup"). Click the blue words that say "set pages".

internet options > programs