Bottom Row of Keys Not Registering

Hi everyone,

I have a Macbook from 2008 that I've had for just under two years now. The bottom row of keys (zxcvbnm,.) often do not register my keystrokes. For example I would push the keys and nothing would happen on screen. Its never been near water, I haven't had the need to clean it with a sponge or anything since I've had it.

I was wondering if Apple could replace my keyboard if I sent it in. I'm unsure since the keys actually work about a third of the time what the best (and least expensive) route to take is.