El Capitan Bootable Disk

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
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El Capitan Bootable Usb

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El Capitan Bootable Dvd Windows

El Capitan Bootable Disk

El Capitan Bootable Disk Installer

Choose the El Capitan bootable disk, and you’ll be led to the following screen. Select Disk Utility which will open up the app. Carefully select your Mac’s system hard drive, and click on Erase in the top section. No criticism, it took me a few tries to create a 'bootable' disk for El Capitan. Anyways, once you have preserved your data, you can try Disk Utility to see if it can fix the problem. If/when it does not it may just be faster to wipe the disk, format it, load El Capitan, then transfer over your data, but that is a royal pain I know.