Adobe Illustrator: Can't see Character preview?, Illustrator CS3: Can't see Character preview?

I'm using Adobe Illustrator CS3 and I can't get the Character pulldown in the toolbar at the top to show me a preview of the typefaces before I select them. They all shown in the same standard typefaces.

How can get I Illustrator to to show me preview of the typefaces in the Character pulldown menu?

Thanks all help much appreciated