How to set my Toshiba to factory settings

Hello,
I have a 2008, or 2009 Toshiba, Windows Vista laptop which suddenly for no reason at all started running extremely slow. I tried everything from removing unwanted files to de-fragmenting it, but nothing helps. I have 2 recovery disc from my Toshiba to reset my computer back to factory setting, but they're not working either. I'm suppose to press F8 repeatedly when starting my computer, but it doesn't work. I need help here. Thanks so much.