How do I reboot my laptop to factory settings?

I just bought a laptop from a guy at my job for 120$. Before I even mess wih it I want to reboot it. Its an Acer laptop running Windows XP I believe even though it has A Vista sticker on it. The way I reboot my desktop when I need to is to unplug it and it gives you the option when it tells you about the improper shutdown. Its been a while but I think thats how I did it. I found sytem restore but that only goes back to previous checkpoint. Help.