MacBook doesn't start - blank screen... logic board?

Whenever I go to class, I usually lock my MacBook so my roommate/anyone who goes in can't get to it. I came back today to a black screen that wouldn't go to the locked log in screen. So I force shutdown the Mac. I turned it back on and not much happened.

I can hear the hard drive and maybe something else whirring. Otherwise, the screen remains blank, the light on the front never goes on, and my optical drive doesn't do its normal startup sound. There's no chime. I can hear it turn off if I hold down the power button.

I tried pulling out the RAM and restarting the SMC. Same problem.

The logic board is gone, isn't it?

Anything else I can try before I start looking at new Macs?