erased hd now el capitan won't finish downloading

Decided to wipe HD and reinstall el capitan which was on my old iMac. After erasing the HD, I tried to install software. It shows it downloading, timer gets to 0, blinks then goes back to over an hour, times down to 0 then blinks and goes back to 1 hr and 7 minutes. At this point the timer no longer counts down. The log shows NUMEROUS errors. I have tried cleaning PRAM, no help. I've tried to do the install using both option-cmmd-r and just cmmd-r, neither worked. I've tried searching for ways to fix this but none have worked so far. I have a disk drive on it and an old snow leopard install disk but can't get it to boot from it. My old mac is an 8.1 @ 2.66gHz with 4096 mb ram. Any help with this is appreciated.