Turns on but keyboard unresponsive?

Okay,

So I got this used white Macbook from a family friend. The laptop will turn on if I press the power button and the trackpad works.

However the keys don't respond. Like no caps lock, no typing, no numbers nothing.

So I'm wondering where I should start in my effort to get this machine back and running?

I've used DVDs, can log to the Internet.

So the macbook seems to work fine for the most part, I'm just wondering how to fix this keyboard problem. I don't see any visible damage on top of the keyboard or sides.

Any ideas? Disassemble? Software issue?

Just looking for some pointers :)