Hi, I also need help with this. I have a 2008 MacBook Pro that has El Capitan on it. I wanted to erase the drive and decommission the machine or let my 6yr old play with it. I went through a 7 Pass erase through the Recovery Startup. Then there was the option to Install Mac OS from within the Recovery Mode. I chose that and the app wanted to install El Capitan and said it needs to download extra content. It asked me to sign into iTunes then it downloaded the files. Maybe 20 minutes later the screen went back to the Recovery menu. I tried it 2 more times and it would not go through the install and there were no errors/warnings.
I then did Disk Utility First Aid and there were no issues. So I tried to install 10.4, 10.5 and 10.7 via disk and when I choose boot from CD/DVD the machine reboots and the disk starts up and runs continuously. The apple logo is on the screen with the spinning circle and nothing happens after about 10 minutes I shut it down.
At this point the machine doesn't work so I tried to restore via Time Machine and that worked fine. I then created a bootable USB for El Capitan following the Apple Support page instructions which went fairly smooth. I rebooted and chose the USB drive to boot/install from but this time the machine booted into Recovery Mode. I tried again thinking I must have chosen the wrong option but same result. I then I tried to choose the USB from the Recovery Mode startup option and yet it still boots into Recovery.
Lastly I went to the Recovery Mode Security utility to check on the firmware to see if other boot options were turned off and the password was off so that wasn't the issue.
Does anyone have a clue of what is going on here? I can't boot from DVD/USB and can't reinstall OSX from Recovery. I'm at a total loss at this point. Is my only option to get my personal data off is to create a new user and delete my user account?