MacBook Pro does not see hard drive on startup

My MacBook Pro suddenly stopped booting, it just displays a folder with a question mark. After reading Apple Support, I booted while pressing the Option key and got into the Startup Utility. I went into the Disk Utility, and it sees the drive and it passes verification tests. However when attempt to reinstall using the Snow Leopard DVD, the install doesn't see the hard drive. Any suggestions as to why the disk utility sees the drive, and neither startup or install do not?