Macbook failure..."No bootable device..."

I have a four-month old Macbook (running Snow Leopard). I used Bootcamp to run Windows 7 on it for a while but then decided against that idea and gave the whole hard drive back to OS X. It ran Win 7 okay, by the way, but I just decided against continuing with it. When I switched it all back OS X it appeared to format the drive just fine but soon after when I started the Macbook I got a black screen with this message: "No bootable device -- insert boot disk and press any key." I inserted the boot disk and there's no response at all, whether or not any key is pressed. The screen display stays the same. I've not been able to eject the disk either. All I'm able to do is power it up or off with the power key. Any helpful ideas? I work in Pakistan, and am a long way from any Genius Bar or service center. I'd appreciate any comments, advice, etc, and thanks in advance.

With the Snow Leopard disk in power on your MacBook while holding the Option key.
Hopefully after a minute or so you'll get disc icon on screen that when selected will boot into the snow lepard installer.

If you get to the "Welcome to OS X Snow Leopard" screen click next. the next page will have a menu bar at the top with Utilities and access to Disk Utility where you can opt to repait the disk etc.

Good Luck