Bad hard drive cable leads to flashing question mark
The mac was giving it the beach ball. After forcing restart, it would not boot up and was flashing question mark folder. It did not detect the hard drive when trying to restore with the osx cd. After reading the forums on this website, I concluded that it was the hard drive cable.
The repair was very easy. I followed the steps in the guide at this website and everything went smoothly.
There is nothing wrong with the hard drive. If your hard drive is out of warranty, I recommend buying the hard drive cable for only $40 to repair it. It works like new.