I´m getting a bit rusty on the old problem solving it´s been a while since I ran into any sort of trouble (with my Mac, that is), but while you wait for other replies, here goes:
The folder with ? mark means your computer can´t find a valid System on your computer. I guess "Tried C key" means you´ve tried starting from the System DVD that came with your MacBook. If that didn´t work
Have you installed any 3rd party RAM? If so, remove it and try again. Also, make sure you have no external units attached via USB/FW, like keyboard, mouse, HD
If this did not resolve your issue, try zapping the parameter RAM (PRAM):
Press and hold the Command-Option-P-R keys as you start up. (You must press this key combination before the gray screen appears.)
Hold the keys down until the computer restarts and you hear the startup sound for the second time.
Release the keys.
http://docs.info.apple.com/article.html?artnum=58042
Best of luck!!
If I don't have the disc that come with my macbook pro, how?