I have a 2009 iMac 24" screen running Leopard 10.5.8; using WD My Book Essential 2TB as a backup. I just went into the iMac's system preferences to dim the screen brightness and by mistake double clicked 'some setting' and now the display's fonts are 1/3 larger than they had been. I think the usual resolution setting had been 1024 by 768 but when I clicked on that it didn't return to normal. My question: how do I access the previous display settings on the backup drive and restore them to what they were earlier today or yesterday? Thanks for your help.