Alright, I am planing on selling my MBP. I needed to erase everything and reinstall OS X. I reformatted the drive, everything went ok. It started to install 10.5 but part way through the install, it froze at a time. I let it sit for about an hour. No change. Trying to click any of the menu icons at the top resulted in beach balling. I then, after reading advice, hard shut off the machine and rebooted to retry the install. Now, I just get a folder with a question mark and, when pressing "c" to have it boot from disk, it reads it, then ejects it. I need help to fix the problem. This is on a Macbook Pro Late 2007 edition. Thanks for the help.