El Capitan won't install

Hi,

My 21.5-inch (Late 2012) iMac refuses to install El Capitan, even after telling it to do a fresh install from the recovery menu.

I've downloaded the app to install it, and it starts off great... until it needs to do it's first restart.

It tries to keep going, restarts itself only to boot up with the "Your Mac has encountered a problem and needed to restart" white screen of death.

Additionally, if I let the installer try to keep going, there's black text that pops up on the left side of the screen, warning of a kernel panic with "PenCommService" from what I can tell.

I have a time machine backup and I've tried a total of two times as of now. Here are the specs from the "About this Mac" screen:

Processor: 1.7 GHz Intel Core i5

Memory: 8GB 1600 MHz DDR3

Graphics: NVIDIA GeForce GT 640M 512 MB

I've already run a diagnostics (by holding down D at startup, as instructed by the Apple support page) only to find that there were no problems.

Is there something I'm missing that could help install El Capitan on my Mac?