Trying to reinstall El Capitan on iMac
I'm wanting to sell my older imac so yesterday I ran the Disk Utility to erase the hard drive (7 passes). When I attempt to reinstall the El Capitan OS from the DU menu, I get the message, "To download and restore OSX your computer eligibility will be verified with Apple". When I click continue a new msg pops up: "A required download is missing". After researching, I shutdown the computer and started up while holding down Option-Command-R to enter to Start Internet Recovery. The computer found my wifi and I entered the password, but the screen didn't change and a little icon next to the wifi kept spinning. It sat there for about 45 min before I shut down the computer. Also, sometimes when I do Option-Command-R - I get the spinning glob and progress bar, but nothing happens and I don't expect it to since it never allowed me to connect to the internet.
I'm wondering if I need a firmware update? Or... my drive isn't partitioned correctly after the erase?
iMac 21.5″, OS X 10.11