on laptops, there usually is a square slot on the underside of it that opens when you unscrew it, which exposes the ram. you could get by on 512mb in vista, but you would probably want to upgrade t a gig. just make sure that if you buy the laptop, in there is only one stick of 512, and not 2 sticks of 256, becuase then yo upgrade to a gig you would need to get rid of both sticks and get 2 512's or 1 stick of a gig, where if in the laptop there was one stick of 512 and one empty slot, all you would need to do is buy another stick of 512 and you have a gig. so ya, it would be good to have 2 gigs, but 1 gig will probably do fine. what do you pla to be doing oin it?