Cannot Install Os X El Capitan

My machine: mid 2007 24' iMac, 2 GB RAM Intel Duo, 667MHz, 2.8GHz, 500GB HD, superdrive, OS X 10.8
The install of El Capitan, at least what I thought was the installation, took a while. A screen shows up with the 10.11 logo stating to install click continue, agree to terms and install OS, I got the option to use disk utility, time machine or recovery or click the install button. I clicked, installation (from bootable flash drive) it stated to restart, with this done a message came that there was installation media on the destination volume, try again.
I restarted and got a progress bar (Apple logo above) which never fully finished, or it did but nothing happened. After walking away for an hour or two, I powered the machine down, restarted it with the option button to get the start up disk manager but only got the apple logo and progress bar, again. I tried to start in recovery mode, also in safe mode with the progress bar appearing after each attempt.
Obviously, I cannot access the drive to remove whatever install media is present on that disk. What options do I have at this point?
Thank you
I
Without

Cannot Install Os X El Capitan

My machine: mid 2007 24' iMac, 2 GB RAM Intel Duo, 667MHz, 2.8GHz, 500GB HD, superdrive, OS X 10.8
The install of El Capitan, at least what I thought was the installation, took a while. A screen shows up with the 10.11 logo stating to install click continue, agree to terms and install OS, I got the option to use disk utility, time machine or recovery or click the install button. I clicked, installation (from bootable flash drive) it stated to restart, with this done a message came that there was installation media on the destination volume, try again.
I restarted and got a progress bar (Apple logo above) which never fully finished, or it did but nothing happened. After walking away for an hour or two, I powered the machine down, restarted it with the option button to get the start up disk manager but only got the apple logo and progress bar, again. I tried to start in recovery mode, also in safe mode with the progress bar appearing after each attempt.
Obviously, I cannot access the drive to remove whatever install media is present on that disk. What options do I have at this point?
Thank you
I

Process: I created a USB disk with a bootable El Capitan as per this documentation. Plug-in your USB key on a turned-off computer. Start your Mac, press immediately OPTION (aka ALT) Select the Orange icon (aka a USB stick) labelled El Capitan. If it does not detect it after 10 sec and you only see your hard-drive.

Cannot Install Os X El Capitan

  • Here is a simple solution to fixing the error message while trying to download your Apple Operating System to Macbook Pro Air via USB drive. If this doesn't.
  • The install of El Capitan, at least what I thought was the installation, took a while. A screen shows up with the 10.11 logo stating to install click continue, agree to terms and install OS, I got the option to use disk utility, time machine or recovery or click the install button.